The association of pre-neoadjuvant SUVmax and post-neoadjuvant change in SUVmax on FDG-PET with survival after oesophagectomy for cancer.

Background: 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is currently widely used in staging and re-staging oesophageal cancer after neoadjuvant therapy. The maximal standardized uptake value (SUVmax) is a reproducible parameter that may predict survival. This study aimed to determine the prognostic significance of SUVmax and the change in SUVmax after neoadjuvant treatment (ΔSUVmax) on overall and disease-free survival.

Methods: FDG-PET data were obtained for patients undergoing radical oesophagectomy between 2008-2021 across three oesophageal cancer centres in Sydney, Australia. Receiver operating characteristics (ROC) curve were used to calculate an optimal cut-off for SUVmax, separating the group into high and low SUVmax, and high and low ΔSUVmax.

Results: 344 patients (median age 67, 80.5% male, 78.7% adenocarcinomas) were included who had FDG-PET data available. The optimal cut-offs for SUVmax was 9.05, and for ΔSUVmax was 22%. The high SUVmax group had lower median OS (54.4 vs. 87.3 months, p<0.001) and lower median DFS (42.7 vs. 78.9 months, p<0.001). The high ΔSUVmax group had a higher median OS (62 vs. 56 months, p=0.031), with similar DFS. On univariate analysis, high SUVmax, high ΔSUVmax, T3 disease, and node negativity were associated with OS. On multivariate analysis, node negativity and ΔSUVmax were independent prognostic factors for OS.

Conclusion: High pre-treatment SUVmax was associated with reduced overall and disease-free survival, but was not an independent prognostic factor on multivariate analysis. On multivariate analysis, a decrease in SUVmax was an independent prognostic. Quantifiable parameters from FDG-PET are hence useful for prognostication prior to radical oesophagectomy.