LAUSR

The aim of this study was to examine the survival effect of adjuvant therapy in stage II–III endometrial cancer based on peritoneal cytology results. The National Cancer Institute’s Surveillance, Epidemiology, and End Results Program was retrospectively queried to examine 7467 women with stage II–III endometrial cancer who underwent hysterectomy, and with available peritoneal cytology results, from 2010 to 2016. A Cox proportional hazard regression model was fitted to assess the association between adjuvant therapy and all-cause mortality stratified by peritoneal cytology results. Malignant peritoneal cytology was reported in 1662 (22.3%) women and was associated with non-endometrioid histology, higher tumor stage, and nodal metastasis (p < 0.05). In a propensity score-weighted model, malignant peritoneal cytology was associated with increased all-cause mortality compared with negative peritoneal cytology (hazard ratio 1.35, 95% confidence interval 1.23–1.48). Adjuvant therapy types varied based on histology and peritoneal cytology results. In non-endometrioid histology, the combination of chemotherapy and whole pelvic radiotherapy (WPRT) was associated with improved overall survival compared with chemotherapy or WPRT alone irrespective of the peritoneal cytology results (p < 0.05). The combination of chemotherapy and WPRT was also associated with improved overall survival in women with endometrioid histology and malignant peritoneal cytology (p = 0.026). Women with endometrioid histology and negative peritoneal cytology represented the most common subpopulation (46.5%), and overall survival was similar regardless of which of the three adjuvant therapy modalities was used (p = 0.319). Malignant peritoneal cytology is prevalent and prognostic in stage II–III endometrial cancer. This study found that the surgeon’s choice and benefit of adjuvant therapy for women with stage II–III endometrial cancer differed depending on the status of peritoneal cytology.