Purpose: The impact of neoadjuvant chemotherapy (NAC) on patients with neuroendocrine carcinoma (NEC) and mixed adenoneuroendocrine carcinoma (MANEC) of the stomach is unclear. The aim of this retrospective study was to evaluate the effects of NAC on patients with these conditions.
Methods: This study included patients with locally advanced NEC or MANEC of the stomach who underwent gastrectomy. Histologic and prognostic effects of NAC were assessed. The overall survival (OS) rate was used to compare treatment efficacies between NAC patients and surgery-first patients.
Results: Of the 69 patients included in this study, 20 received NAC and 49 underwent surgery first after diagnosis. A total of 13 patients responded to NAC (including 3 with complete remission and 10 with partial remission) and 7 patients acquired stable disease status according to the Response Evaluation Criteria in Solid Tumors version 1.1. One patient (5%) achieved a pathological complete response after NAC. Pathological tumor regression grades 1, 2, 3, 4, and 5 were observed in 1 (5%), 5 (25%), 3 (15%), 10 (50%), and 1 (5%) patient(s) with NAC, respectively. The incidence of postoperative complications was similar in the two groups. Patients in the NAC group demonstrated better OS than did patients in the surgery-first group (P = 0.032). Multivariate analyses showed that NAC, adjuvant chemotherapy, and the clinical N stage were independent factors affecting OS.
Conclusion: In patients with locally advanced NEC and MANEC of the stomach, NAC significantly improved OS.
Keywords: Mixed adenoneuroendocrine carcinoma; Neoadjuvant chemotherapy; Neuroendocrine carcinoma; Stomach.