Therapy-Based Analysis in Ovarian Small Cell Neuroendocrine Carcinoma: A Case Series on Surgical, Chemotherapeutic, and Immunotherapeutic Outcomes

Abstract Background: Neuroendocrine neoplasms (NENs) of the female reproductive tract are extremely rare, accounting for 1–2% of gynecological malignancies. Primary ovarian small cell neuroendocrine carcinoma (SCNEC) is an aggressive subtype with uncertain origin, early metastasis, and poor prognosis. Methods: We retrospectively analyzed seven cases of primary ovarian SCNEC diagnosed at Yunnan Cancer Hospital between August 2015 and January 2025, focusing on clinical features, treatment, and outcomes. Results: The median age was 47 years (14–72). Clinical stages were I (1), III (3), and IV (3). Common symptoms included abdominal pain, distension, and painless masses. Median tumor diameter was 12 cm (6–19), and all patients had elevated CA-125 and NSE. All underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy; five received postoperative platinum-based chemotherapy. One HRD/BRCA-negative stage IVB patient progressed after EP and TC combined with tislelizumab; another IVB patient developed brain metastases after EP plus bevacizumab and received whole-brain radiotherapy. At follow-up, 2 were disease-free, 2 lost to follow-up, 2 recurred, and 1 died of disease progression. Conclusion: Primary ovarian SCNEC is highly aggressive with poor prognosis. Despite surgery and chemotherapy, recurrence is common, and immunotherapy may be ineffective in advanced cases. Early detection and novel treatment strategies are urgently needed.