The value of ¹⁸F-FDG PET as a predictor of survival in patients with gastro-oesophageal junction (GEJ) adenocarcinoma

Ziel/Aim The prospective, multicenter DKTK phase II study MEMORI has shown the feasibility of PET response guided treatment adjustments in patients with locally gastro-esophageal junction carcinomas undergoing neoadjuvant therapy. However, there is still a significant variation on overall and recurrence free survival in the group of PET responders. The aim of this study was to evaluate if survival of PET responders could be further stratified by FDG PET metrics.

Methodik/Methods FDG PET/CT scans of 70 patients suffering from GEJ adenocarcinoma and who received a three-step treatment approach of induction chemotherapy (CTX) and either perioperative CTX or chemoradiotherapy (CRT) were evaluated. Based on a prospective PET-guided treatment stratification (continuing CTX if ≥35 % decrease in SUV_mean from baseline; change to CRT if <35 % decrease in SUV_mean from baseline) 47/70 (67,1 %) and 23/70 (32,9 %) patients were subgrouped as PET-responders (PET-R; subsequent CTX) and PET-nonresponders (PET-NR; subsequent CRT), respectively. For our analysis in the group with PET-R a volume of interest (VOI) was manually drawn around the tumors by one nuclear medicine physician. Using a threshold-based analysis (SUV threshold of 4,0 and 42 %), SUV_max, SUV_mean, metabolic tumor volume (MTV) and total lesion glycolysis (TLG), as well as change of these parameters from baseline to follow-up 18F-FDG PET scans were measured. The value of these parameters to predict OS and RFS were evaluated using the median of the parameters and Kaplan-Meier method.

Ergebnisse/Results Baseline SUV_mean (median 8,03) and baseline SUV_max (median 13,64) came closest to a significant stratification of OS (HR 0,31, 95 % CI, 0,08-1,183, p = 0,09). However, none of the 18F-FDG PET parameter were significantly related to OS or RFS.

Schlussfolgerungen/Conclusions Although baseline SUV_mean and baseline SUV_max showed promising results, no 18F-FDG PET parameter could provide a further significant stratification of OS and RFS in patients with GEJ adenocarcinoma with a previous PET-guided treatment stratification.

Publication History

Article published online:
08 April 2021