Effect of neoadjuvant chemotherapy on survival in patients with gastric signet ring cell adenocarcinoma: A multicentric comparative study.

Abstract

4036 Background: Perioperative chemotherapy is a standard treatment for gastric adenocarcinoma (GA). Signet ring cell GA (SRC) has been shown to be of poorer prognosis when compared to non-SRC. Although of major importance in this context, chemosensitivity of SRC remains hypothetical. The aim of this study was to evaluate the survival impact of neoadjuvant chemotherapy (NCT) in patients with gastric SRC through a large national comparative cohort. Methods: 1,054 patients were treated for SRC in 18 French centers from 1997 to 2009. Were included patients treated in a curative intent (n=924) with 171 patients who received NCT followed by surgery (NCT arm, 18.5%) compared in intention to treat to 753 patients treated by surgery alone (S arm, 81.5%). NCT, mainly based on a fluorouracil-platinum doublet or triplet, was proposed in some centers in accordance to national guidelines for GA treatment, whereas other centers favored primary surgery for SRC due to the suspected chemoresistance. Results: Both groups were comparable regarding usual prognostic variables such as age, gender, ASA score, malnutrition, tumoral location and TNM stage. Ten patients did not benefit from surgery because of a major tumoral progression meanwhile. At surgical examination, metastases were discovered in 4.8% of patients in NCT group and 8.1% in S group (p=0.130), with no tumoral resection in 50 patients. Among the 864 resected patients, R0 resection rates were 65.9% vs. 62.3%, respectively (p = 0.308). Significantly more patients received adjuvant chemotherapy in the NCT group than in the S group (62% vs. 31%, p<0.001). After a median follow-up of 31.5 months, overall survival was significantly shorter in the NCT group (8.6 vs. 12.7 months, p<0.001). In multivariate analysis, NCT was an independent predictor of poor survival (HR 1.4 95% CI 1.1-1.9, p=0.042). Conclusions: While perioperative chemotherapy is considered a standard treatment for GA regardless of histological subtype, we demonstrate for the first time that NCT provides no survival benefit in SRC. Registered on Clinicaltrial.gov website under identifier NCT01249859.