Prognostic significance of SUV on PET/CT in patients with localised oesophagogastric junction cancer receiving neoadjuvant chemotherapy/chemoradiation:a systematic review and meta-analysis

Abstract

Objective: The objective of this study was to comprehensively review the evidence for use of pre-treatment, post-treatment and changes in tumour glucose uptake that were assessed by 18-fludeoxyglucose ((18)F-FDG) positron emission tomography (PET) early, during or immediately after neoadjuvant chemotherapy/chemoradiation to predict prognosis of localised oesophagogastric junction (AEG) cancer.

Methods: We searched for articles published in English; limited to AEG; (18)F-FDG uptake on PET performed on a dedicated device; dealt with the impact of standard uptake value (SUV) on survival. We extracted an estimate of the log hazard ratios (HRs) and their variances and performed meta-analysis.

Results: 798 patients with AEG were included. And the scan time for (18)F-FDG-PET was as follows: prior to therapy (PET1, n=646), exactly 2 weeks after initiation of neoadjuvant therapy (PET2, n=245), and pre-operatively (PET3, n=278). In the two meta-analyses for overall survival, including the studies that dealt with reduction of tumour maximum SUV (SUV(max)) (from PET1 to PET2/PET3 and from PET1 to PET2), the results were similar, with the overall HR for non-responders being 1.83 [95% confidence interval (CI), 1.41-2.36] and 2.62 (95% CI, 1.61-4.26), respectively; as for disease-free survival, the combined HR was 2.92 (95% CI, 2.08-4.10) and 2.39 (95% CI, 1.57-3.64), respectively. The meta-analyses did not attribute significant prognostic values to SUV(max) before and during therapy in localised AEG.

Conclusion: Relative changes in FDG-uptake of AEG are better prognosticators. Early metabolic changes from PET1 to PET2 may provide the same accuracy for prediction of treatment outcome as late changes from PET1 to PET3.

Figure 1

Review: meta-analyses of the studies dealt with the prognostic value of response in maximum standardised uptake value measured by fludeoxyglucose positron emission tomography (PET) (a) at least 2 weeks [from prior to therapy (PET1) to 2 weeks after initiation of neoadjuvant therapy (PET2) or pre-operatively] and (b) exactly 2 weeks (from PET1 to PET2) after initiation of therapy for overall survival. Results in (a) indicate that metabolic responders from PET1 to PET2/PET3 had a better overall survival than metabolic non-responders; results in (b) indicate that metabolic responders from PET1 to PET2 had a better overall survival than metabolic non-responders. CI, confidence interval; HR, hazard ratio; SE, standard error.

Figure 2

Funnel graph for the assessment of potential publication bias in studies of response in standard uptake value in patients with oesophagogastic junction cancer. (a) The studies for overall survival and (b) the studies for disease-free survival. HR, hazard ratio; SE, standard error.

Figure 3

Review: meta-analyses of the studies dealt with the prognostic values of the maximum standardised uptake value measured by fludeoxyglucose positron emission tomography (a) prior to therapy and (b) at least 2 weeks after the initiation of therapy (at 2 weeks after the initiation of neoadjuvant therapy or pre-operatively) for overall survival. Results in (a) indicate that a high primary tumour maximum standard uptake value (SUV_max) at positron emission tomography 1 (PET1) was not associated with a worse overall survival prognosis. Results in (b) indicate that a high primary tumour SUV_max at PET2/PET3 was not associated with a worse overall survival prognosis. CI, confidence interval; HR, hazard ratio; SE, standard error.

Figure 4

Review: meta-analyses of the studies dealt with the prognostic value of response in maximum standardised uptake value measured by fludeoxyglucose positron emission tomography (PET) (a) at least 2 weeks [from prior to therapy (PET1) to exactly 2 weeks after initiation of neoadjuvant therapy (PET2) or pre-operatively] and (b) exactly 2 weeks after initiation of therapy (from PET1 to PET2) for disease-free survival. Results in (a) indicate that metabolic responders from PET1 to PET2/PET3 had a better disease-free survival (DFS) than metabolic non-responders. Results in (b) indicate that metabolic responders from PET1 to PET2 had a better DFS than metabolic non-responders. CI, confidence interval; HR, hazard ratio; SE, standard error.