Objective  Neuroendocrine carcinomas (NECs) of the digestive tract are rare and show aggressive behavior. Radical surgery can be performed in patients with non-metastatic disease; however, rapid recurrence and metastasis often occur after surgery, leading to a poor clinical prognosis. The role of postoperative adjuvant chemotherapy (PAC) in these patients remains controversial. Moreover, clinical research data are lacking, and there is no recommended standard treatment. Therefore, this study aimed to determine whether PAC is associated with a survival benefit in patients with NECs of the digestive tract compared to surgical resection alone.

  Methods  Sixty-two patients who met the inclusion criteria between June 2018 and September 2020 were included in the study. We performed a retrospective analysis of patients with NECs of the digestive tract who underwent radical surgery; the patients were divided into two groups, the PAC group and postoperative observation (PO) group, according to whether they had received postoperative chemotherapy. At least two cycles of platinum-based chemotherapy were administered within 4-6 weeks post-surgery in patients who received PAC. The primary endpoint was the 2-year disease-free survival (DFS) rate. The secondary endpoint was the DFS rate with respect to different adjuvant chemotherapy regimens.

  Results  Of the 62 patients, 52 (83.9%) were male and 10 (16.1%) were female; the median age was 65 (range, 38-84) years. Twelve patients had esophageal neuroendocrine carcinomas (19.3%), 45 had stomach neuroendocrine carcinomas (72.6%), and five had small intestine and colorectal NECs (8.1%). Thirty-eight patients (61.3%) received PAC: 21 patients (33.9%) received etoposide plus cisplatin and 17 patients (27.4%) received irinotecan plus cisplatin. More than four cycles of chemotherapy were administered to 21 patients. The PO group contained 24 patients (38.7%). The 2-year DFS rates in the PAC and PO groups were 58.7% and 14.7%, respectively (P < 0.001). Multivariate analyses demonstrated that in patients with positive lymph nodes, PAC could significantly improve survival (P=0.020, HR: 6.403, 95% CI: 1.329-27.465).

  Conclusions  Patients with neuroendocrine carci-nomas of the digestive tract who underwent radical resection can experience improved DFS after PAC, which reduces the risk of recurrence and metastasis after surgery. However, the choice of PAC regimen needs to be verified in further studies.