IMPACT OF ADJUVANT CHEMOTHERAPY ON SURVIVAL OF PATIENTS WITH RESECTABLE LOCALLY ADVANCED GASTROESOPHAGEAL JUNCTION OR GASTRIC ADENOCARCINOMA SUBMITTED TO PERIOPERATIVE CHEMOTHERAPY

Background: Gastric cancer has a poor prognosis. Perioperative chemotherapy with FLOT (Fluorouracil, Oxaliplatin and Docetaxel) or FOLFOX (Fluorouracil, Oxaliplatin and Leucovorin) are important treatment for resectable locally advanced gastroesophageal junction (GEJ) or gastric adenocarcinoma. However, limited toxicity often causes early discontinuation of treatment. The aim of this study is to evaluate the impact on disease-free survival (DFS) of reducing the dose of adjuvant FLOT or FOLFOX on patients diagnosed with locally advanced GEJ or gastric adenocarcinoma undergoing perioperative chemotherapy. Methods: A single center retrospective study which included patients diagnosed with resectable locally advanced GEJ or gastric adenocarcinoma between January of 2014 to July of 2020. Primary endpoint was DFS among patients who received complete versus (vs) incomplete adjuvant treatment (reduced dose or no treatment). Prognostic factors were assessed using univariate and multivariate Cox analysis. A p value <0.05 was considered significant. Results: Among the 107 patients included, 81 (75.7%) were diagnosed with gastric adenocarcinoma and 90 (84.1%) had TNM clinical stage III tumors. Most patients (56.1%) received FLOT neoadjuvant treatment. 43 (52.4%) patients received FLOT adjuvant and 39 (47.6%) received FOLFOX. A total of 31 (29%) patients completed adjuvant treatment and 76 (71%) patients did not complete treatment. Median follow up time was 46 months (95% Confidence Interval [CI] 41.1-50.8 months) and no difference on DFS was demonstrated between adjuvant treatment complete versus incomplete (median not demonstrated for complete adjuvant treatment and 42 months, 95% CI 19.264.7 for incomplete adjuvant treatment, p=0.870). In Cox’s analysis for DFS, incomplete neoadjuvant treatment and absence of pathological response were considered independent variants of worse prognosis, with a Hazard Ratio (HR) of 4.17 (95% CI 1.90 – 9.17, p=0.0001) and HR of 6.44 (95% CI 1.54 – 26.95, p=0.001), respectively. Conclusion: In perioperative chemotherapy, performance of adjuvant chemotherapy doesn’t impact on prognosis of patients with locally advanced GEJ or gastric adenocarcinoma which received complete course of neoadjuvant FLOT or FOLFOX.