OBJECTIVE: We conducted a retrospective, multi-institutional, collaborative study to accumulate cases of neuroendocrine carcinoma of the endometrium, to clarify its clinicopathologic features, treatment, prognosis and prognostic factors to collate findings to establish future individualized treatment regimens. To our knowledge, this is the largest case study and the first study to statistically analyze the prognosis of this disease. METHODS: At medical institutions participating in the Kansai Clinical Oncology Group/Intergroup, cases diagnosed at a central pathologic review as neuroendocrine carcinoma of the endometrium between 1995 and 2014 were enrolled. We retrospectively analyzed the clinicopathologic features, treatment, prognosis and prognostic factors of this disease. RESULTS: A total of 65 cases were registered from 18 medical institutions in Japan. Of these, 42 (64.6%) cases were diagnosed as neuroendocrine carcinoma of the endometrium based on the central pathological review and thus included in the study. Advanced International Federation of Gynecology and Obstetrics stages (stage III and IV) and pure type small cell neuroendocrine carcinoma cases had a significantly worse prognosis. Upon multivariate analysis, only histologic subtypes and surgery were significant prognostic factors. Pure type cases had a significantly worse prognosis compared to mixed type cases and complete surgery cases had a significantly better prognosis compared to cases with no or incomplete surgery. CONCLUSION: Our findings suggest that complete surgery improves the prognosis of neuroendocrine carcinoma of the endometrium. Even among cases with advanced disease stages, if complete surgery is expected to be achieved, clinicians should consider curative surgery to improve the prognosis of neuroendocrine carcinoma of the endometrium.
Carcinoma, Large Cell ; Carcinoma, Neuroendocrine ; Carcinoma, Small Cell ; Endometrial Neoplasms ; Endometrium ; Female ; Gynecology ; Japan ; Medical Oncology ; Multivariate Analysis ; Obstetrics ; Prognosis ; Retrospective Studies

Objectives: This review aims to introduce preoperative scoring systems to predict lymph node metastasis (LNM) and ongoing clinical trials to investigate the therapeutic role of lymphadenectomy for endometrial cancer. Methods: We summarized previous reports on the preoperative prediction models for LNM and evaluated their validity to omit lymphadenectomy in our recent cohorts. Next, we compared characteristics of two ongoing lymphadenectomy trials (JCOG1412, ECLAT) to examine the survival benefit of lymphadenectomy in endometrial cancer, and described the details of JCOG1412. Results: Lymphadenectomy has been omitted for 64 endometrial cancer patients who met lowrisk criteria to omit lymphadenectomy using our scoring system (LNM score) and no lymphatic failure has been observed. Other two models also produced comparable results. Two randomized phase III trials to evaluate survival benefit of lymphadenectomy are ongoing for endometrial cancer. JCOG1412 compares pelvic lymphadenectomy alone with pelvic and para-aortic lymphadenectomy to evaluate the therapeutic role of para-aortic lymphadenectomy for patients at risk of LNM. For quality assurance of lymphadenectomy, we defined several regulations, including lower limit of the number of resected nodes, and submission of photos of dissected area to evaluate thoroughness of lymphadenectomy in the protocol. The latest monitoring report showed that the quality of lymphadenectomy has been well-controlled in JCOG1412. Conclusion Our strategy seems reasonable to omit lymphadenectomy and could be generalized in clinical practice. JCOG1412 is a high-quality lymphadenectomy trial in terms of the quality of surgical procedures, which would draw the bona-fide conclusions regarding the therapeutic role of lymphadenectomy for endometrial cancer.