Coverage Policy Manual
Policy #: 2011074
Category: Radiology
Initiated: December 2011
Last Review: December 2023
  PET or PET/CT for Gastric and Hepatocellular and Biliary Tract Cancers
Description:
Positron Emission Tomography (PET) imaging uses radiotracers that can reveal both anatomical and physiological information. The glucose analog, 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) is useful in cancer imaging because it has been found that tumor cells show increased utilization of glucose compared to non-malignant tissue and is the most common radiotracer that is utilized. For certain malignancies PET scans have been shown to be more accurate than other non-invasive tests in detecting malignant disease. However, as with all diagnostic tests, PET scans do not detect cancer 100% of the time that cancer is present (a false negative test), nor do all positive PET scans represent the presence of malignant disease (a false positive test). A false negative test may occur because a critical volume of malignant cells is necessary for a PET scan to be positive. PET scans may be false positive in the presence of inflammation or granulomatous disease.
 
There are no controlled studies on the effectiveness of PET scan imaging for gastric cancer or cancer of the gastroesophageal junction.  It is known that only 50% of gastric cancers are FDG-avid, which has resulted in a recommendation that PET scan alone is not recommended for evaluating adenocarcinoma of the stomach or gastroesophageal junction.  PET/CT, however , has improved on the imaging results.
 
Definitions
 
Screening – testing in the absence of an established or clinically suspected diagnosis
 
Diagnosis - testing based on a reasonable clinical suspicion of a particular condition or disorder
 
Diagnostic Workup – initial staging of documented malignancy
 
Management – testing to direct therapy of an established condition, which may include preoperative or postoperative imaging, or imaging performed to evaluate the response to nonsurgical intervention. In oncologic imaging, management applies to patients with measurable disease and to imaging performed before or after planned treatment intervention, therapy response, restaging or clinically suspected recurrence.
 
Surveillance – periodic assessment following completion of therapy. In oncologic imaging, surveillance applies to asymptomatic patients in remission and/or without measurable disease
 
Cannot be performed or is nondiagnostic – applies when the test:
    • Is positive or indeterminate for clinically significant pathology when the information provided about the abnormality by the test is not sufficient to direct subsequent management
    • Is negative when the negative likelihood ratio of the test is both insufficient to confidently exclude the absence of suspected disease and unable to direct subsequent management. This typically applies in scenarios with moderate to high clinical pretest probability with negative testing or low pretest probability with clear evidence for net benefit
    • Has been previously nondiagnostic because of a persistent clinical factor (e.g., body habitus, immobility) that is very likely to make retesting nondiagnostic as well Cannot be performed due to a medical contraindication (e.g., contrast nephrotoxicity, allergy, or in highly radiation sensitive populations such as pediatrics and pregnancy) or reasonable unavailability related to lack of local expertise or service availability
Standard or conventional imaging: Refers to imaging that does not require a PET/CT. Depending on the clinical scenario and individual patient circumstances, this may include computed tomography, magnetic resonance imaging, ultrasound and/or scintigraphy.
Policy/
Coverage:
EFFECTIVE MARCH 14, 2024
 
Gastric Cancer
 
Meets Primary Coverage Criteria Or Is Covered For Contracts Without Primary Coverage Criteria
 
FDG-PET/CT meets member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes for:  
Diagnostic Workup:
        • Indicated for tumors initially stage IB or higher when standard imaging cannot be performed or does not demonstrate distant (M1) metastatic disease, and the patient is a candidate for curative surgery  
Management:
Indicated in ANY of the following scenarios:
        • Radiation planning for preoperative or definitive treatment only
        • To determine resectability of residual disease following completion of primary (neoadjuvant) treatment, when follow-up evaluation with standard modalities does not demonstrate metastatic disease
        • Clinical suspicion for recurrent disease when standard imaging cannot be performed or is nondiagnostic for recurrent or progressive disease
 
For all fully insured contracts, all self-funded church-sponsored health plans and all self-funded government-sponsored health plans other than the Arkansas State and Public School Employees program, the Federal Employee Health Benefit Program and Medicare Advantage plans, as required by Act 583 of the Arkansas Legislature, please see ABCBS policy 2021004, Surveillance and Other PET Oncologic Applications.
 
Does Not Meet Primary Coverage Criteria Or Is Investigational For Contracts Without Primary Coverage Criteria
 
PET/CT for patients with Gastric Cancer does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes:  
    • Surveillance*
For contracts without primary coverage criteria, PET/CT for patients with Gastric Cancer is considered investigational and is not covered for any other indication not specifically listed as covered above including by not limited to:
    • Surveillance
Investigational services are Plan exclusions.
 
*For all fully insured contracts, all self-funded church-sponsored health plans and all self-funded government-sponsored health plans other than the Arkansas State and Public School Employees program, the Federal Employee Health Benefit Program and Medicare Advantage plans, as required by Act 583 of the Arkansas Legislature, please see ABCBS policy 2021004, Surveillance and Other PET Oncologic Applications.
 
Hepatocellular and Biliary Tract Cancers
 
Meets Primary Coverage Criteria Or Is Covered For Contracts Without Primary Coverage Criteria
 
FDG-PET/CT meets member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes for:
Diagnostic Workup:
        • Indicated when standard imaging cannot be performed or is nondiagnostic regarding the extent of disease
Management:
        • Indicated when standard imaging cannot be performed or is nondiagnostic for recurrent or progressive disease
 
For all fully insured contracts, all self-funded church-sponsored health plans and all self-funded government-sponsored health plans other than the Arkansas State and Public School Employees program, the Federal Employee Health Benefit Program and Medicare Advantage plans, as required by Act 583 of the Arkansas Legislature, please see ABCBS policy 2021004, Surveillance and Other PET Oncologic Applications.
 
Does Not Meet Primary Coverage Criteria Or Is Investigational For Contracts Without Primary Coverage Criteria
 
PET/CT for patients with Hepatocellular and Biliary tract cancers does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes:  
    • Surveillance*
For contracts without primary coverage criteria, PET/CT for patients with Hepatocellular and Biliary tract cancers is considered investigational and is not covered for any other indication not specifically listed as covered above including by not limited to:
    • Surveillance*
Investigational services are Plan exclusions.
 
*For all fully insured contracts, all self-funded church-sponsored health plans and all self-funded government-sponsored health plans other than the Arkansas State and Public School Employees program, the Federal Employee Health Benefit Program and Medicare Advantage plans, as required by Act 583 of the Arkansas Legislature, please see ABCBS policy 2021004, Surveillance and Other PET Oncologic Applications.
Note: Standard or conventional imaging: Refers to imaging that does not require a PET/CT. Depending on the clinical scenario and individual patient circumstances, this may include computed tomography, magnetic resonance imaging, ultrasound and/or scintigraphy.
 
EFFECTIVE MARCH 13, 2022 to April 13, 2024
 
Meets Primary Coverage Criteria Or Is Covered For Contracts Without Primary Coverage Criteria
 
FDG-PET/CT for patients with Gastric Cancer meets member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes for:
 
Diagnostic Workup:
        • Indicated for tumors initially stage IB or higher when standard imaging cannot be performed or does not demonstrate distant (M1) metastatic disease, and the patient is a candidate for curative surgery
 
Management:
Indicated in ANY of the following scenarios:
        • Radiation planning for preoperative or definitive treatment only
        • To determine resectability of residual disease following completion of primary (neoadjuvant) treatment, when follow-up evaluation with standard modalities does not demonstrate metastatic disease
        • Clinical suspicion for recurrent disease when standard imaging cannot be performed or is nondiagnostic for recurrent or progressive disease
 
For all fully insured contracts, all self-funded church-sponsored health plans and all self-funded government-sponsored health plans other than the Arkansas State and Public School Employees program, the Federal Employee Health Benefit Program and Medicare Advantage plans, as required by Act 583 of the Arkansas Legislature, please see ABCBS policy 2021004, Surveillance and Other PET Oncologic Applications.
 
 
Does Not Meet Primary Coverage Criteria Or Is Investigational For Contracts Without Primary Coverage Criteria
 
PET/CT for patients with Gastric Cancer does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes:  
    • Surveillance*
 
For contracts without primary coverage criteria, PET/CT for patients with Gastric Cancer is considered investigational and is not covered for any other indication not specifically listed as covered above including by not limited to:
    • Surveillance*
Investigational services are specific contract exclusions in most member benefit certificates of coverage.
 
*For all fully insured contracts, all self-funded church-sponsored health plans and all self-funded government-sponsored health plans other than the Arkansas State and Public School Employees program, the Federal Employee Health Benefit Program and Medicare Advantage plans, as required by Act 583 of the Arkansas Legislature, please see ABCBS policy 2021004, Surveillance and Other PET Oncologic Applications.
 
 
Note: Standard or conventional imaging: Refers to imaging that does not require a PET/CT. Depending on the clinical scenario and individual patient circumstances, this may include computed tomography, magnetic resonance imaging, ultrasound and/or scintigraphy.
 
 
Effective Prior to MARCH 13, 2022
 
Meets Primary Coverage Criteria Or Is Covered For Contracts Without Primary Coverage Criteria
 
FDG-PET/CT for patients with Gastric Cancer meets member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes for:
 
Diagnostic Workup
Indicated when ALL the following are met:
      • Tumor(s) initially stage IB or higher when standard imaging cannot be performed; AND
      • Does not demonstrate M1 metastatic disease; AND
      • The patient is a candidate for curative surgery.
 
Treatment Management
Indicated in ANY of the following:
      • Radiation planning for preoperative or definitive treatment only; or
      • To determine resectability of residual disease following completion of primary (neoadjuvant) treatment, when follow-up evaluation with standard modalities does not demonstrate metastatic disease; or
      • Clinical suspicion for recurrent disease when standard imaging cannot be performed or is nondiagnostic.
 
For all fully insured contracts, all self-funded church-sponsored health plans, and all self-funded government-sponsored health plans (e.g., state and public-school employee plans), other than the Federal Employee Health Benefit Program and Medicare Advantage plans, as required by Act 583 of the Arkansas Legislature, please see ABCBS policy 2021004, Surveillance and Other PET Oncologic Applications.
 
 
Does Not Meet Primary Coverage Criteria Or Is Investigational For Contracts Without Primary Coverage Criteria
 
PET/CT for patients with Gastric Cancer does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes:  
    • For screening and surveillance; or
    • For any other indication not specifically listed above.
 
 
For contracts without primary coverage criter, PET/CT for patients with Gastric Cancer is considered investigational:  
    • For screening and surveillance; or
    • For any other indication not specifically listed above.
Investigational services are specific contract exclusions in most member benefit certificates of coverage.
 
 
Effective Prior to August 2021
 
Meets Primary Coverage Criteria Or Is Covered For Contracts Without Primary Coverage Criteria
 
FDG-PET/CT for patients with Gastric Cancer meets member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes for:
 
Diagnostic Workup  
Indicated when ALL the following are met:  
      • Tumor(s) initially stage IB or higher when standard imaging cannot be performed; AND
      • Does not demonstrate M1 metastatic disease; AND
      • The patient is a candidate for curative surgery.
 
Treatment Management  
Indicated in ANY of the following:  
      • Radiation planning for preoperative or definitive treatment only; or
      • To determine resectability of residual disease following completion of primary (neoadjuvant) treatment, when follow-up evaluation with standard modalities does not demonstrate metastatic disease; or
      • Clinical suspicion for recurrent disease when standard imaging cannot be performed or is nondiagnostic.
 
Does Not Meet Primary Coverage Criteria Or Is Investigational For Contracts Without Primary Coverage Criteria
 
PET/CT for patients with Gastric Cancer does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes:  
    • For screening and surveillance; or
    • For any other indication not specifically listed above.
 
For members with contracts without primary coverage criteria, PET/CT for patients with Gastric Cancer is considered investigational:  
    • For screening and surveillance; or
    • For any other indication not specifically listed above.
Investigational services are specific contract exclusions in most member benefit certificates of coverage.
 
 
Effective Prior to June 15, 2021
 
Meets Primary Coverage Criteria Or Is Covered For Contracts Without Primary Coverage Criteria
 
PET scan imaging meets member certificate of benefit Primary Coverage Criteria for effectiveness for
  • Initial staging of gastric cancer as an adjunct to other imaging in developing a treatment plan
  • Restaging following completion of initial therapy, if initial staging showed tumor to be FDG avid
  • Restaging following subsequent chemotherapy or radiotherapy regimens, if initial staging showed tumor to be FDG avid
  • Monitoring during adjuvant chemotherapy to predict survival (MUNICON Trial, 2007)
  • Restaging for suspected recurrence of disease based on clinical, laboratory, or other radiological findings, if initial staging showed tumor to be FDG avid
 
 
Does Not Meet Primary Coverage Criteria Or Is Investigational For Contracts Without Primary Coverage Criteria
 
PET scan imaging does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes for:
  • PET scan imaging with PET alone (Dassen, 2009)
  • Diagnosis in lieu of biopsy
  • Surveillance of asymptomatic patients post therapy (Podoloff, 2009; NCCN Guidelines, V1, 2013)
  • Monitoring during neoadjuvant chemoradiation to predict response or survival (NEOPEC Trial, 2011)
 
For contracts without primary coverage criteria, PET without CT is considered investigational in the following indications:
  • PET scan imaging with PET alone (Dassen, 2009)
  • Diagnosis in lieu of biopsy
  • Surveillance of asymptomatic patients post therapy (Podoloff, 2009; NCCN Guidelines, V1, 2013)
  • Monitoring during neoadjuvant chemoradiation to predict response or survival (NEOPEC Trial, 2011)
 
Investigational services are considered specific contract exclusions in most member benefit certificates of coverage.
Rationale:
NCCN Guidelines, Version 2.2012
    •  Routine use of PET/CT is not recommended.  PET/CT scans may be warranted in some situations.
    •  PET/CT has a low detection rate because of the low tracer accumulation in diffuse and mucinous tumor types which are frequent in gastric cancer.  It has a significantly lower sensitivity compared to CT in the detection of local lymph node involvement, although it has an improved specificity.  Combined PET/CT imaging, on the other hand, has several potential advantages over PET scan alone.  PET/Chas a significantly higher accuracy in the preoperative staging than PET or CT alone.  Recent reports have confirmed that PET alone is not an adequate diagnostic procedure in the detection and preoperative staging of gastric cancer but it could be helpful when used in conjunction with CT.
 
Canadian Agency for Drugs and Technologies in Health (Mujoomdar, 2010)
The April 2010 Canadian Agency for Drugs and Technologies in Health assessment of PET in Oncology does not include an assessment of PET for gastric carcinoma.  
 
NCCN Task Force Report (Podoloff DA, 2009)  
The Podoloff, et al review discusses the use of PET for gastric carcinoma but it is noted that as much as half of primary gastric tumors are FDG-negative. If a tumor is FDG-avid then PET may detect metastatic disease not identified by other imaging modalities.    
    
Diagnosis/initial staging: not for diagnosis; potential use for detection of metastatic disease.   
            
Restaging/recurrence: no specific comment.               
    
Surveillance: No specific comment, but the Podoloff recommends surveillance only in the context of a clinical trial.
 
Monitoring:  the 2003 Ott study, and the MUNICON trial are discussed.
 
National Oncologic PET Registry reports, 2008 (Hillner) and 2009 (Hillner)
The 2008 review describes a 35.5% impact of PET (of PET/CT) on intended management for restaging, and 29.3% impact on intended management for detection of suspected recurrence. The 2009 report, which was directed to “Expected management during cancer treatment” addresses monitoring, and no useful information was presented.
 
No controlled studies with comparison groups have been published. No studies on the effect of PET on overall survival have been published; and no comparative studies on the effect of PET on patient outcome (other than from Kaplan-Meier curves) have been published.  All published reports as of the date of this coverage statement, are from small series of patients.  
 
Ott K, et al, 2008
Long-term outcomes from the 2003 study.  Identified three different metabolic groups.  17 of 49 metabolic responders at 14 days after initiation of chemotherapy showed a high histopathologic response rate (69%) and a favorable prognosis, whereas metabolic nonresponders (32 of 49) had a poor prognosis and showed a histopathologic response in 17%.  The histopathologic response rate (24%) for FDG-PET non-avid patients showed no significant difference compared with FDG-avid nonresponders.  Survival of FDG non-avid patients was 36.7 months which was not significantly different from FDG-avid nonresponders.
 
Sim SH, et al., 2009  
Retrospective study of 52 patients who were post curative resection of gastric cancer, who were followed with PET/CT and contrast CT, imaged for recurrence. Recurrence of gastric cancer was validated by histologic confirmation (n=17) or serial contrast CT with at least 5-month intervals (n= 35). Thirty-eight patients were confirmed as recurrence. Sensitivity was 68.4% for PET/CT (26/38) and 89.4% for contrast CT (34/38). Specificity was 71.4% and 64.2% respectively. The authors concluded PET/CT was a sensitive and specific as contrast CT in detection of recurrent gastric cancer (except peritoneal seeding) but additional PET/CT on contrast CT did not increase diagnostic accuracy in detection of recurrent gastric cancer.  
 
Ozkan E, et al., 2011  
Thirty-six gastric cancer patients: Group 1 - preop staging (n=4); Group 2 - posttherapy evaluation (n=24); Group 3 - suspicion of local recurrence and/or metastasis (n=8). Retrospective analysis of 42 PET/CT scans compared with concurrent CT results. Groups 1 and 3 omitted due to small numbers of patients. Overall concordance rate was 50%. Region based analysis showed rates of concordance for local recurrence, lymph node metastasis and distant metastasis were 91%, 95% and 50% respectively.  
 
Bilici A, et al., 2011  
PET/CT retrospectively analyzed in 34 patients suspected of having recurrent gastric cancer after previous curative gastrectomy and lymph node dissection. PET/CT was positive in 23 patients, negative in 11 (one false neg, histopathologically confirmed recurrence). The overall sensitivity, specificity, accuracy, positive and negative predictive values of PET/CT compared to diagnostic CT were 95.8 vs 62.5%, 100 vs 10%, 97 vs 47%, 100 vs 62.5% and 90.9 vs 10%, respectively, p=0.012) in this group of patients. PET/CT results changed patient management in 18 cases by leading to the use of previously unplanned treatment procedures in 9 patients and the avoidance of previously planned therapeutic procedures in 9 patients.  
 
Wang, Chen, 2011  
Systematic review of available literature in multiple databases to provide overview of imaging in predicting the status of the liver and peritoneum pre-therapeutically. Thirty-three studies were included (8 US, 5 EUS, 22 CT, 2 MRI, 18 PET – methodological quality considered moderate). Meta-analysis showed CT to be the most sensitive imaging method with a high rate of specificity in detecting hepatic metastasis, and EUS most sensitive in detecting peritoneal metastasis. The two MRI studies had both high sensitivity and specificity in detecting liver metastasis.  
 
Ha et al., 2011  
PET/CT compared to multi-detector row CT (MDCT) in 78 patients with pathologically confirmed gastric cancer diagnosed at endoscopy.  Primary tumors detection: 51 patients with PET/CT and 47 patients with MDCT.  Detection of lymph node metastasis: sensitivity 51.5% with 71.8% accuracy with PET/CT vs 69.7% and 69.2% with MDCT. The sensitivity of PET/CT for a primary tumor of signet ring carcinoma was lower than that for PET/CT for a primary tumor with non-signet ring cell carcinoma (35.3 vs 73.8%).  
 
These authors concluded there was no definite clinical benefit for prediction of lymph node metastasis in preoperative staging of gastric cancer using PET/CT.  
 
Seevaratnam et al., 2011  
“The agreement between pr-operative TNM staging by imaging scans and post-operative staging by pathology is not perfect and may affect treatment decisions.”  For pre-operative T staging MRI scans had better performance accuracy than CT and AUS; better performance with CT scanners using 4 or more detectors and multi-planar reformatted (MPR) images.  For pre-operative N staging PET had the lowest sensitivity but highest specificity than other modalities. CT performance not affected by detector number or addition of MPR images.  For pre-operative M staging performance did not significantly differ by modality, detector number or MPR images.  
 
Wu, 2012
Systematic review and meta-analysis of FDG PET in detecting recurrent gastric cancer.  This study looked principally at PET scan only and found sensitivity to be 0.78, and specificity 0.82.
  
2014 Update
A systematic review and meta-analysis pooled 9 studies on evaluating recurrent gastric cancer  (Wu, 2012).   The meta-analysis used methods that do not adequately account for dependence of sensitivity and specificity, nor do they adequately handle covariates that might explain between-study heterogeneity. It concluded that PET combined with CT may be more effective than either modality alone, but the data presented do not support this conclusion. In a 2013 meta-analysis, the sensitivity of PET-CT for detecting recurrence of gastric cancer after surgical resection was 0.86 (95% CI, 0.71 to 0.94), and specificity was 0.88 (95% CI, 0.75 to 0.94) (Zhou, 2013).
 
The NCCN guidelines on gastric cancer indicate PET-CT (but not PET alone) may be used as part of an initial workup if there is no evidence of metastatic disease. (V2.2013). The guidelines note the sensitivity of PET-CT is lower than CT, but the specificity is higher than CT and adds value to the diagnostic workup. The NCCN guidelines also indicate PET-CT may be used to evaluate response to treatment.
  
2015 Update
A literature search conducted through January 2015 did not reveal any new information that would prompt a change in the coverage statement.
 
2017 Update
A literature search conducted through February 2017 did not reveal any new information that would prompt a change in the coverage statement.  
 
2018 Update
 
Annual policy review completed with a literature search using the MEDLINE database through February 2018. No new literature was identified that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
GASTRIC CANCER AND 18F-FDG-PET AND 18F-FDG-PET/CT
A 2016 systematic review by Li et al evaluated 18F-FDG-PET and 18F-FDG-PET/CT for detecting recurrent gastric cancer (Li, 2016). The literature search, conducted through February 2015, identified 14 studies (total N=828 patients) to be included in the analysis. The analysis combined both imaging techniques; 3 studies used PET alone and 11 studies used PET/CT. Pooled sensitivity and specificity were 85% (95% CI, 75% to 92%) and 78% (95% CI, 72% to 84%), respectively.
 
Evidence for the use of PET to diagnose recurrent gastric cancer consists of meta-analyses. One metaanalysis evaluated 18F-FDG-PET alone, one evaluated 18F-FDG-PET/CT, and another combined the 2 techniques into a single estimate. Sensitivity estimates ranged from 78% to 85% and specificity estimates ranged from 78% to 88%. The evidence supports the use of 18F-FDG-PET and 18F-PET/CT for the diagnosis and staging and restaging of esophageal cancer, but does not support their use for surveillance.
 
2019 Update
Annual policy review completed with a literature search using the MEDLINE database through February 2019. No new literature was identified that would prompt a change in the coverage statement.
 
 
2020 Update
A literature search was conducted through February 2020.  There was no new information identified that would prompt a change in the coverage statement.  
 
2021 Update
Annual policy review completed with a literature search using the MEDLINE database through January 2021. No new literature was identified that would prompt a change in the coverage statement.
 
December 2021 Update
A literature review was performed through September 2021. Following is a summary of the key literature to date.
 
DIAGNOSTIC WORKUP
Gastric cancer is staged using the American Joint Committee on Cancer TNM system. Endoscopic ultrasound (EUS) is used to obtain pathologic confirmation of malignancy and local tumor staging, with advanced imaging used to assess lymph nodes and metastases. (1) In a meta-analysis of 50 studies, EUS for assessment of locoregional disease showed sensitivity and specificity rates for distinguishing T1 from T2 cancers of 85% and 90%, respectively. Sensitivity and specificity for distinguishing T1/2 from T3/4 tumors were 86% and 90%, respectively. When used to evaluate lymph nodes, EUS had a lower diagnostic yield with sensitivity and specificity of 83% and 67%, respectively.1A second metaanalysis reported accuracy rates for tumor staging at 75% and nodal staging at 64% with a sensitivity of 74% and
specificity of 80%. (2) In a third systematic review comparing EUS, CT, and MRI, the diagnostic accuracy of overall T staging for EUS, multidetector CT, and MRI varied between 65% to 92.1%, 77.1% to 88.9%, and 71.4% to 82.6%, respectively. The authors concluded that although efficacy was similar, EUS remains the standard of care. (3) The accuracy of CT for assessing primary tumor is only 50%-70% and for nodal staging 50%-64%.4, 5CT performs better with regard to metastatic disease, with an accuracy of 79%-84%. (6) In contrast, FDG-PET has a lower accuracy rate because of the low FDG uptake common to diffuse and mucinous gastric tumor types. (7, 8)
 
However, combining PET and CT leads to improved accuracy in preoperative staging (68%) compared to PET (47%) or CT (53%) alone, and in a single-institution retrospective study, changed management in 38% of patients. (9) The major advantage conferred by PET is improved specificity over CT for the detection of distant metastases (M1 disease). Smyth et al reported in a prospective study that PET/CT identified an additional 10% occult metastatic lesions in patients with locally advanced disease, compared to preoperative CT imaging, EUS, and laparoscopy. (10) FDG PET/CT is recommended if no evidence of M1 disease by standard imaging and if clinically indicated (may not be appropriate for T1 disease) by National Comprehensive Cancer Network (NCCN) (level of evidence category 2A). (11)
MANAGEMENT
The results of studies showing response to therapy as evidenced by FDG-PET have been mixed. A prospective observation trial by Vallbohmer et al showed no correlations between interval PET findings and change in FDG avidity to response or prognosis.12 In another study, survival of patients without FDG-avid disease was not significantly different from FDG-avid non-responders.13 In the setting of recurrent disease, a retrospective study showed overall sensitivity and specificity of 78% and 82% for PET compared to 74% and 85% for CT, respectively. (14) Therefore, NCCN recommends chest/abdominal/pelvic CT scan for medically fit patients after the completion of preoperative therapy
(chemotherapy or chemoradiation) and before surgical intervention, with PET as clinically indicated. (11)
 
SURVEILLANCE
The majority of gastric cancer recurrences occur locoregionally in the lymph nodes and peritoneum, followed by the liver. A retrospective Italian trial, which included patients with T1-4 N0-3 M0 gastric cancer who had undergone D2 dissection, found that 94% recurred within 2 years and 98% recurred within 3 years. Of the recurrences, only 3.2% were treated with curative intent. (15) In a review of 5 articles that included 810 patients, intense surveillance with CT imaging did not show an improvement in survival. (16) Based on the National Comprehensive Cancer Network (NCCN) Guidelines for Gastric Cancer, surveillance imaging for patients with stage II or greater gastric cancer can be done as clinically indicated based on symptoms and concern for recurrence; after 5 years, additional follow-up may be considered based on risk factors and comorbidities.
 
References
    1. Mocellin S, Pasquali S. Diagnostic accuracy of endoscopic ultrasonography (EUS) for the preoperative locoregional staging of primary gastric cancer. Cochrane Database Syst Rev. 2015(2):CD009944. PMID: 25914908
    2. Cardoso R, Coburn N, Seevaratnam R, et al. A systematic review and meta-analysis of the utility of EUS for preoperative staging for gastric cancer. Gastric Cancer. 2012;15 Suppl 1:S19-26. PMID: 22237654
    3. Kwee RM, Kwee TC. Imaging in local staging of gastric cancer: a systematic review. J Clin Oncol. 2007;25(15):2107-16. PMID: 17513817
    4. Dux M, Richter GM, Hansmann J, et al. Helical hydro -CT for diagnosis and staging of gastric carcinoma. J Comput Assist Tomogr. 1999;23(6):913-22. PMID: 10589566
    5. Rossi M, Broglia L, Maccioni F, et al. Hydro-CT in patients with gastric cancer: preoperative radiologic staging. Eur Radiol. 1997;7(5):659-64. PMID: 9166562
    6. Lee IJ, Lee JM, Kim SH, et al. Diagnostic performance of 64-channel multidetector CT in the evaluation of gastric cancer: differentiation of mucosal cancer (T1a) from submucosal involvement (T1b and T2). Radiology. 2010;255(3):805-14. PMID: 20501718
    7. Stahl A, Ott K, Weber WA, et al. FDG PET imaging of locally advanced gastric carcinomas: correlation with endoscopic and histopathological findings. Eur J Nucl Med Mol Imaging. 2003;30(2):288-95. PMID: 12552348
    8. Wieder HA, Krause BJ, Herrmann K. PET and PET-CT in esophageal and gastric cancer. Methods Mol Biol. 2011;727:59-76. PMID: 21331929
    9. Blencowe NS, Whistance RN, Strong S, et al. Evaluating the role of fluorodeoxyglucose positron emission tomography-computed tomography in multi-disciplinary team recommendations for oesophago-gastric cancer. Br J Cancer. 2013;109(6):1445-50. PMID: 23963146
    10. Smyth E, Schoder H, Strong VE, et al. A prospective evaluatio n of the utility of 2-deoxy-2-[(18) F]fluoro-D-glucose positron emission tomography and computed tomography in staging locally advanced gastric cancer. Cancer. 2012;118(22):5481-8. PMID: 22549558
    11. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Gastric Cancer (Version 2.2021). Available at http://www.nccn.org. ©National Comprehensive Cancer Network, 2021
    12. Vallbohmer D, Holscher AH, Schneider PM, et al. [18F]-fluorodeoxyglucose-positron emission tomography for the assessment of histopathologic response and prognosis after completion of neoadjuvant chemotherapy in gastric cancer. J Surg Oncol. 2010;102(2):135-40. PMID: 20648583
    13. Ott K, Herrmann K, Lordick F, et al. Early metabolic response evaluation by fluorine-18 fluorodeoxyglucose positron emission tomography allows in vivo testing of chemosensitivity in gastric cancer: long-term results of a prospective study. Clin Cancer Res. 2008;14(7):2012-8. PMID: 18381939
    14. Wu LM, Hu JN, Hua J, et al. 18 F-fluorodeoxyglucose positron emission tomography to evaluate recurrent gastric cancer: a systematic review and meta-analysis. J Gastroenterol Hepatol. 2012;27(3):472-80. PMID: 21916986
    15. Baiocchi GL, Marrelli D, Verlato G, et al. Follow-up after gastrectomy for cancer: an appraisal of the Italian research group for gastric cancer. Ann Surg Oncol. 2014;21(6):2005-11. PMID: 24526547
    16. Cardoso R, Coburn NG, Seevaratnam R, et al. A systematic review of patient surveillance after curative gastrectomy for gastric cancer: a brief review. Gastric Cancer. 2012;15 Suppl 1:S164-7. PMID: 22382929
 
2022 Update
Annual policy review completed with a literature search using the MEDLINE database through September 2022. No new literature was identified that would prompt a change in the coverage statement.
 
NCCN Guidelines for Gastric Cancer Version 2022 were reviewed with no change from Version 2021 with regard to PET applications in Gastric Cancer.
 
2023 Update
Annual policy review completed with a literature search using the MEDLINE database through November 2023. No new literature was identified that would prompt a change in the coverage statement.
 
2024 Update
A literature review was performed through January 2024. Following is a summary of the key literature to date.
 
DIAGNOSTIC WORKUP
Hepatobiliary cancer (including gallbladder cancer, cholangiocarcinoma and hepatocellular carcinoma) is staged using the American Joint Committee on Cancer TNM system.
 
Hepatocellular Carcinoma (HCC)
The initial staging evaluation of suspected HCC should include either a multiphasic abdominal CT or MRI to establish the diagnosis and assess the burden of disease. The National Comprehensive Cancer Network (NCCN) also recommends CT or MRI if positive or rising serum AFP is found during HCC screening.(1)
 
A diagnosis of HCC can be made based on imaging criteria in patients at high risk for developing HCC; the most commonly used guidelines are published by the American Association for the Study of Liver Disease (AASLD), which incorporates the American College of Radiology (ACR) Liver Imaging Reporting and Data System (LI-RADS).(2) In a systematic review and meta-analysis evaluating the diagnostic performance of multidetector CT and MRI, the overall per-patient sensitivity of MR imaging was 88% (95% CI, 83%-92%) and per-patient specificity was 94% (95% CI, 85%-98%). An insufficient number of studies disallowed pooled analysis of CT for diagnostic accuracy and comparison to MRI, but the overall per-lesion sensitivity of MR imaging was higher than that of multidetector CT when the paired data of the 11 available studies were pooled (80% vs 68%, P = .0023). In addition, MRI sensitivity was further improved when gadoxetic acid-enhanced MR imaging was used. Sensitivity tends to be worse in both modalities for lesions < 1cm.(3)
 
Extrahepatic imaging should include CT of the chest and pelvis if not already done. Bone scan may be useful when clinical suspicion of bone metastases is high. In a retrospective study comparing PET and conventional imaging for initial diagnosis of HCC, PET identified additional metastases in 2.7% of patients with T2, 5.3% of patients with T3a (5.3%), and 4.8% of patients with T3b tumor classifications. In a systematic review and meta-analysis, the pooled estimates of sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of FDG PET for the detection of metastatic hepatocellular carcinoma were 76.6%, 98.0%, 14.68, and 0.28, respectively.(4) Although PET imaging may provide prognostic information on the biological aggressiveness of the cancer, the low sensitivity restricts its usefulness.(5)
 
Cholangiocarcinoma and Gallbladder Cancer
In patients with suspected cholangiocarcinoma/gallbladder cancer, CT chest and multi-detector, multiphasic CT of the abdomen and pelvis should be performed to assess local disease, lymph nodes, and sites of distant metastases. If an intervention is not required and accurate imaging of the pancreatobiliary tract is needed to assess surgical resectability, an MRI abdomen with magnetic resonance cholangiopancreatography (MRCP) should be considered. MRCP has largely replaced endoscopic retrograde cholangiopancreatography (ERCP) as it provides better anatomical imaging, a non-invasive alternative with lower risk of complications, and at least equivalent accuracy.(6-10) In a systematic review and meta-analysis comparing CT, MRI, and PET to assess for resectability of hilar cholangiocarcinoma, CT had the highest pooled sensitivity at 95% (95% CI, 91%-97%) and a pooled specificity of 69% (63%-75%). MRI had a pooled sensitivity of 94% (90%-97%) and a pooled specificity of 71% (60%-81%), whereas PET/CT had a pooled sensitivity of 91% (84%-96%), and the highest pooled specificity at 81% (95% CI, 69%-90%). The area under the curves (AUC) of CT, MRI, and PET/CT were 0.9269, 0.9194, and 0.9218, respectively. Overall, CT and MRI are comparable imaging modalities to assess resectability. (11) The data to support use of PET/CT for initial staging of cholangiocarcinoma is mixed, although some studies show a change in management of 17%-25%. (12-14) Overall, PET imaging has limited sensitivity for local evaluation of cholangiocarcinoma, although high specificity for detection of nodal and distant metastatic disease. Per NCCN recommendations, PET/CT may be considered when equivocal findings are seen by CT or MRI imaging and prior to planned resection.
 
MANAGEMENT
Response to treatment can be assessed with multiphasic CT or MRI of the abdomen, as both can assess intra-nodular arterial vascularity, a key feature of residual or recurrent tumor. Overall nodule size does not reliably indicate treatment response since a variety of factors may cause a successfully treated lesion to appear stable in size or even larger after treatment. The NCCN notes for hepatocellular cancer “PET/CT has limited sensitivity but high specificity, and may be considered when there is an equivocal finding.” [REF]
 
SURVEILLANCE
In patients treated with curative intent, follow-up for HCC includes CT or MRI imaging of the liver, and consideration for CT chest imaging. Monitoring of AFP is appropriate for HCC. Carelon Oncologic Imaging guidelines are in concordance with the NCCN Guidelines for Hepatobiliary Cancer.49
 
Current References
    1. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Hepatobiliary Cancers (Version 1.2023). Available at http://www.nccn.org. ©National Comprehensive Cancer Network, 2022.
    2. Marrero JA, Kulik LM, Sirlin CB, et al. Diagnosis, staging, and management of hepatocellular carcinoma: 2018 practice guidance by the American Association for the Study of Liver Diseases. Hepatology. 2018;68(2):723-50.
    3. Lee YJ, Lee JM, Lee JS, et al. Hepatocellular carcinoma: diagnostic performance of multidetector CT and MR imaging-a systematic review and meta-analysis. Radiology. 2015;275(1):97-109.
    4. Cho Y, Lee DH, Lee YB, et al. Does 18F-FDG positron emission tomography-computed tomography have a role in initial staging of hepatocellular carcinoma? PLoS ONE. 2014;9(8):e105679.
    5. Lin CY, Chen JH, Liang JA, et al. 18F-FDG PET or PET/CT for detecting extrahepatic metastases or recurrent hepatocellular carcinoma: a systematic review and meta-analysis. Eur J Radiol. 2012;81(9):2417-22.
    6. Sun DW, An L, Wei F, et al. Prognostic significance of parameters from pretreatment (18)F-FDG PET in hepatocellular carcinoma: a meta-analysis. Abdom Radiol. 2016;41(1):33-41.
    7. Hyodo T, Kumano S, Kushihata F, et al. CT and MR cholangiography: advantages and pitfalls in perioperative evaluation of biliary tree. Br J Radiol. 2012;85(1015):887-96.
    8. Szklaruk J, Tamm E, Charnsangavej C. Preoperative imaging of biliary tract cancers. Surg Oncol Clin N Am. 2002;11(4):865-76.
    9. Vogl TJ, Schwarz WO, Heller M, et al. Staging of Klatskin tumours (hilar cholangiocarcinomas): comparison of MR cholangiography, MR imaging, and endoscopic retrograde cholangiography. Eur Radiol. 2006;16(10):2317-25.
    10. Yeh TS, Jan YY, Tseng JH, et al. Malignant perihilar biliary obstruction: magnetic resonance cholangiopancreatographic findings. Am J Gastroenterol. 2000;95(2):432-40.
    11. Zidi SH, Prat F, Le Guen O, et al. Performance characteristics of magnetic resonance cholangiography in the staging of malignant hilar strictures. Gut. 2000;46(1):103-6.
    12. Zhang H, Zhu J, Ke F, et al. Radiological imaging for assessing the respectability of hilar cholangiocarcinoma: a systematic review and meta-analysis. Biomed Res Int. 2015;2015:497942.
    13. Corvera CU, Blumgart LH, Akhurst T, et al. 18F-fluorodeoxyglucose positron emission tomography influences management decisions in patients with biliary cancer. J Am Coll Surg. 2008;206(1):57-65.
    14. Petrowsky H, Wildbrett P, Husarik DB, et al. Impact of integrated positron emission tomography and computed tomography on staging and management of gallbladder cancer and cholangiocarcinoma. J Hepatol. 2006;45(1):43-50.
    15. Ruys AT, Bennink RJ, van Westreenen HL, et al. FDG-positron emission tomography/computed tomography and standardized uptake value in the primary diagnosis and staging of hilar cholangiocarcinoma. HPB. 2011;13(4):256-62.
 
 
CPT/HCPCS:
78811Positron emission tomography (PET) imaging; limited area (eg, chest, head/neck)
78812Positron emission tomography (PET) imaging; skull base to mid thigh
78813Positron emission tomography (PET) imaging; whole body
78814Positron emission tomography (PET) with concurrently acquired computed tomography (CT) for attenuation correction and anatomical localization imaging; limited area (eg, chest, head/neck)
78815Positron emission tomography (PET) with concurrently acquired computed tomography (CT) for attenuation correction and anatomical localization imaging; skull base to mid thigh
78816Positron emission tomography (PET) with concurrently acquired computed tomography (CT) for attenuation correction and anatomical localization imaging; whole body
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Fletcher JW, Djulbegovic B, Soares HP, et al.(2008) Recommendations on the use of 18F-FDG PET in oncology. J of Nucl Med, 2008; 49:480-508.

Ha TK, Choi YY, et al.(2011) F18-fluorodeoxyglucose-positron emission tomography and computed tomography is not accurate in preoperative staging of gastric cancer. J Korean Surg Soc, 2011; 11:104-10.

Hillner BE, Siegal BA, Shields AE, et al.(2009) The impact of positron emission tomography (PET) on expected management during cancer treatment. Cancer, 2009; 115:410-418.

Hillner BE, Siegel BA, Shields AF, et al.(2008) Relationship between cancer type and impact of PET and PET/CT on intended management: Findings of the National Oncologic PET Registry. J Nucl Med, 2008; 49:1928-2161.

Li P, Liu Q, Wang C, et al.(2016) Fluorine-18-fluorodeoxyglucose positron emission tomography to evaluate recurrent gastric cancer after surgical resection: a systematic review and meta-analysis. Ann Nucl Med. Apr 2016;30(3):179-187. PMID 26830546

Lordick F, Ott K, Krause BJ, et al.(2007) PET to assess early metabolic response and to guide treatment of adenocarcinoma of the oesophagogastric junction: the MUNICON phase II trial. Lancet Oncol, 2007; 8:797-805.

Lorenzen S, von Gall C, Stange A, et al.(2011) Sequential FDG-PET and induction chemotherapy in locally advanced adenocarcinoma of the oesophago-gastric junction (AEG): The Heidelberg Imaging program in Cancer of the oesophago-gastric junction during neoadjuvant treatment: HICON trial. BMC Cancer, 2011; 11:266.

Mujoomdar M, Moulton K, Nkansah E.(2010) Positron emission tomography in oncology: A systematic review of clinical effectiveness and indications for use. Ottawa: Canadian Agency for Drugs & Technologies in Health.

National Comprehensive Cancer Network(2022) NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Gastric Cancer (Version 2.2022). Available at http://www.nccn.org. ©National Comprehensive Cancer Network, 2022

National Comprehensive Cancer Network.(2011) NCCN Guidelines, Version 2.2011, Gastric Cancer. www.nccn.org. Last accessed Nov 2011.

National Comprehensive Cancer Network.(2012) NCCN Guidelines, Version 2.2012, Gastric Cancer. www.nccn.org. Accessed 2012-10-25.

Ott K, Fink U, Becker K, et al.(2003) Prediction of response to preoperative chemotherapy in gastric carcinoma by metabolic imaging: results of a prospective trial. J Clin Oncol, 2003; 15:4604-4610.

Ott K, Herrmann K, Lordick F, et al.(2008) Early metabolic response evaluation by fluorine-18 fluorodeoxyglucose positron emission tomography allows in vivo testing of chemosensitivity in gastric cancer: Long-term results of a prospective study. Clin Cancer Res, 2008; 14:2012-2018.

Ozkan E, Araz M, et al.(2011) The role of 18F-FDG-PET/CT in the preoperative staging and posttherapy follow up of gastric cancer: comparison with spiral CT. World J Surg Oncol, 2011; 9:75.

Podoloff DA, Ball DW, en-Josef E, et al.(2009) NCCN task force report: Clinical utility of PET in a variety of tumor types. JNCCN, 2009; 7 (Suppl 2):S1-S23.

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Wang Z, Chen JQ.(2011) Imaging in assessing hepatic and peritoneal metastases of gastric cancer: a systematic review. BMC Gastroenterology, 2011; 11:19.

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