Objectives (1) To determine the significance of positive peritoneal cytology and pelvic versus para-aortic lymph node involvement in uterine carcinosarcoma. (2) To evaluate the impact of isolated retroperitoneal lymph node involvement (IIIC-N) versus retroperitoneal lymph node involvement plus other evidence of extrauterine disease spread (IIIC-N+) on survival in patients with stage IIIC uterine carcinosarcoma.

Methods Data were extracted from the Surveillance, Epidemiology, and End Results database between 1988 and 2005. Statistical analysis used χ², Kaplan-Meier method, and Cox proportional hazards model.

Results A total of 690 women were identified. When comparing overall survival between patients with disease spread to uterine serosa and/or adnexa and those with positive peritoneal cytology, there was no significant difference (25.4% vs 15.5%, P = 0.2). However, although the 5-year overall survival was comparable between patients with positive pelvic lymph nodes and those with positive para-aortic lymph nodes (22.1% vs 25.4%, P = 1.0), it was significantly worse in stage IIIC-N(+) compared to stage IIIC-N patients (15.0% vs 33.4%, P < 0.001). Only patient’s age (P < 0.001), race (P = 0.03), stage (P < 0.03), and lymphadenectomy (P < 0.001) were independent predictors of survival after adjusting for other contributing factors. In addition, the results of unadjusted analysis concerning the survival difference between different stage groups were confirmed on multivariate analysis.

Conclusions Positive peritoneal cytology is associated with poor prognosis in uterine carcinosarcoma, comparable to current International Federation of Gynecology and Obstetrics stage IIIA classification of disease. Although there does not seem to be a significant survival difference between patients with positive pelvic versus those with para-aortic lymph nodes, the prognosis seems to be much worse in patients with stage IIIC uterine carcinosarcoma with other evidence of extrauterine disease spread, suggesting the need for more aggressive therapy.