Tumor response score with neoadjuvant FLOT versus FOLFOX in gastric cancer patients: Results from a United States-based cohort.

Abstract

e16573 Background: A recent RCT comparing FLOT and ECF regimens for locally advanced gastric cancer found FLOT to be superior in pathologic complete response (PCR) rates: 16% versus 6%. We evaluated patients who underwent resection after FLOT and FOLFOX in a diverse US population. Methods: Patients diagnosed with gastric adenocarcinoma at a single institution who underwent preoperative chemotherapy either with FLOT or FOLFOX between 2017 and 2019 were evaluated for pathologic response. Results: Fifty-nine patients underwent gastrectomy for adenocarcinoma. Of these, 59% underwent neoadjuvant chemotherapy: FLOT 20 patients, FOLFOX 12 patients, ECF 1 patient, other regimen 2 patients. Racial/ethnic background of patients were 20% non-Hispanic white, 23% Hispanic/Latino, 40% Asian, 6% black, and 6% other. Three patients (8.6%) had PCR, two received FLOT and one FOLFOX. Four patients had a near complete response (tumor regression score 1), all of whom received FLOT. In total, 16 of 20 patients who received FLOT had at least a partial response whereas only 5 of 12 patients who received FOLFOX had any tumor response (p = 0.027). Among all patients receiving neoadjuvant chemotherapy, 66% had poorly differentiated tumors. Only 1 of these patients experiencing a complete or near complete response compared to 50% of patients with non-poorly differentiated tumors (p = 0.001). Conclusions: In an ethnically diverse US population, tumor regression rates were improved with FLOT when compared to FOLFOX. For medically appropriate patients, strong consideration should be given for FLOT in the neoadjuvant setting.