Diagnostic accuracy and prognostic factors of uterine serous carcinoma in Japanese women: a multi-center study.

Objective: This multi-center retrospective study aimed to clarify the characteristics, diagnostic accuracy, treatment outcomes, and prognostic factors of uterine serous carcinoma (USC) in Japanese women.

Methods: The medical records of 193 patients who were treated between 2006 and 2008 at 24 participating institutions in the Japanese Clinical Oncology Group were examined, and pathological slides of 188 patients were re-checked through central pathology review (CPR), hematoxylin-eosin staining, and immunohistochemistry.

Results: USC was confirmed in 144 of the 188 (76.6%) patients using CPR, and only 50% were correctly diagnosed preoperatively. Forty-three patients were diagnosed with non-serous carcinoma, whereas one patient had metastasis from another organ. The average age was 65.7 years, and 19% of patients had a history of other cancers. The incidence of stage III-IV disease was 52.8%, and lymph node metastasis was found in 28.5% of patients. Extrauterine spread and distant metastasis occurred in 39% and 14% of patients, respectively. The 2-year overall survival and progression-free survival (PFS) rates were 56% and 42%, respectively. The PFS of patients with stage I and II who underwent complete staging surgery was 92.3%, and that of those without lymph node dissection or omentectomy was 33.3%. Patients with USC had a significantly worse prognosis than 43 patients with non-serous carcinoma.

Conclusion: USC in Japanese women has characteristics different from those of endometrioid carcinoma, worse prognosis, and is difficult to diagnose preoperatively. Complete surgical staging is necessary even for early-stage disease. Additionally, new adjuvant treatment strategies, including molecular targeted therapy, should be explored.