Clinical outcomes of extended neoadjuvant FLOT for resectable gastroesophageal cancer.

356 Background: FLOT4 and ESOPEC established 4 preoperative/4 postoperative cycles of FLOT as the standard of care for nonmetastatic gastroesophageal adenocarcinomas, but 0.05). Clinical T stage was more advanced in cohort B compared to A (p=0.05). Six patients in cohort B were de-escalated from FLOT to FOLFOX (9.5% vs 0%; p=0.07). There were no differences in postoperative complication rates (31.7% vs 21.2%; p=0.28), length of stay (6 vs 7 days; p=0.93), and negative surgical margin rates (96.8% vs 100%; p=0.30). Patients receiving more preoperative chemotherapy were more likely to complete the treatment course (58.7% vs 30.3%; p=0.008) and received a greater total number of cycles overall (8 vs 6; p≤0.001). The groups had similar recurrence rates (7.9% vs 9.1%; p=0.85), overall survival (HR = 1.13, 95% CI: 0.31, 4.05; p=0.9), and disease-free survival (HR = 0.99, 95% CI: 0.31, 3.15; p>0.9), despite a trend toward a higher pathological complete response (pCR) rate for cohort B (26.7% vs 13.8%; p=0.10). Conclusions: In our analysis, extended neoadjuvant chemotherapy increased treatment completion without worsening postsurgical outcomes. Although pCR rates were approximately doubled in the extended neoadjuvant group, the cohort size was insufficient for statistical significance. It is unclear if de-escalation of chemotherapy negates some benefits of FLOT administered for limited doses.