Supplementary Material for: Exploring a Better Adjuvant Treatment for Surgically Treated High-grade Neuroendocrine Carcinoma of the Cervix

Objectives: To explore a better adjuvant treatment for patients with high-grade (HG) neuroendocrine cervical carcinomas (NECC) who had undergone surgery as a primary treatment. Design: A retrospective cohort study, which involved 110 women diagnosed as HG-NECC, was conducted in OB & GYN Hospital of Fudan University. All patients had undergone radical surgery and pelvic lymphadenectomy with a laparotomy or a minimally invasive surgery (MIS). An analysis was made of the prognosis of HG-NECC. Methods: Overall survival (OS) and progression-free survival (PFS) curves were drawn using the Kaplan-Meier method to be compared via log-rank tests. A cox proportional hazards model was used to estimate independent prognostic factors. Results: A number of 110 patients diagnosed as HG-NECC at the pathological stage IA2 to IIIC2 according to the International Federation of Gynecology and Obstetrics (FIGO) 2018 staging system, were initially treated with a primary surgery between 2008 and 2020. The eligible patients had the median age of 42.5 (range: 22-76), with the median follow-up period of 39.6 months (range: 1.0-156.6). The 5-year OS of the patients at pathological stage I, II and III accounted for 84.9%, 85.7% and 60.9%, respectively. The Kaplan-Meier survival curves revealed no significant differences in OS and PFS between post-operative chemoradiotherapy and chemotherapy alone (P=0.27). Etoposide plus platinum therapy did not improve OS when compared with platinum plus paclitaxel therapy after surgery (P=0.71). The univariable analysis showed that chemotherapy with cycles ≥ 4 presented a better prognosis than with cycles < 4 (OS: P=0.01; HR=6.71; PFS:P=0.02; HR=5.18). The multivariate analysis indicated that the cycles of chemotherapy (P=0.02, HR 0.29) was a prognostic factor for PFS. Limitations: A retrospective design and the absence of partial follow-up data. Conclusions: In initially surgically treated HG-NECC, post-operative chemotherapy alone showed no inferiority when compared with chemoradiotherapy for HG-NECC and 4+ cycles of chemotherapy tended to produce a better prognosis than 4- ones.