Purpose: This study was designed to examine the association between malignant peritoneal cytology and survival of women with uterine sarcoma.
Methods: This retrospective, observational study queried the National Cancer Institute's Surveillance, Epidemiology, and End Result Program. Uterine sarcoma cases diagnosed from 2010 to 2016 with known peritoneal cytology results were examined. Propensity score inverse probability of treatment weighting was fitted to balance the measured covariates. Overall survival (OS) was compared between malignant and negative cytology cases.
Results: A total of 1481 uterine sarcomas were examined. Malignant peritoneal cytology was seen in 146 (9.9%) cases. Women who had T3 disease and distant metastases had the highest incidence of malignant peritoneal cytology (43.1%). In multivariable analysis, higher T stage, nodal involvement, distant metastasis, poorer tumor differentiation, and rhabdomyosarcoma/endometrial stromal sarcoma were significantly associated with an increased risk of malignant peritoneal cytology (all, P < 0.05). In the weighted model, malignant peritoneal cytology was associated with a nearly twofold increased risk of all-cause mortality compared with negative peritoneal cytology (3-year OS rate 34.7% versus 60.2%; hazard ratio 2.26; 95% confidence interval 1.88-2.71; P < 0.001). The absolute difference in the 3-year survival rate was particularly large in leiomyosarcoma (3-year OS rate 2.8% versus 51.9%; hazard ratio 2.64; 95% confidence interval 1.94-3.59; P < 0.001). Malignant peritoneal cytology was also associated with an increased all-cause mortality risk in early and advanced stages (both, P < 0.05).
Conclusions: Our study suggests that malignant peritoneal cytology may be a prognostic factor for increased mortality in uterine sarcoma, particularly in uterine leiomyosarcoma.