Correlation between malignant peritoneal cytology and survival in patients with uterine leiomyosarcoma and endometrial stromal sarcoma.

OBJECTIVE: This study aimed to examine the correlation between malignant peritoneal cytology and overall survival among patients with uterine leiomyosarcoma and endometrial stromal sarcoma.

METHODS: Patients with uterine leiomyosarcoma and endometrial stromal sarcoma between January 2010 and December 2016 were identified from the Surveillance, Epidemiology, and End Results database. The multiple imputation method was used to address missing values. Propensity score matching was conducted to balance baseline data between the malignant and negative peritoneal cytology groups. The prognostic significance of malignant peritoneal cytology was evaluated using Cox regression, random survival forest, and subgroup analyses.

RESULTS: Among 733 eligible patients, 8% (59/733) had malignant peritoneal cytology, increasing to 20% (42/209) in advanced cases. Before and after propensity score matching, patients with malignant peritoneal cytology had significantly lower 5-year overall survival rates and shorter median survival time than patients with negative peritoneal cytology. Multivariate Cox regression revealed that malignant peritoneal cytology (hazard ratio 2.03, 95% confidence interval 1.29 to 3.20, p=0.002) was an independent prognostic factor for uterine leiomyosarcoma and endometrial stromal sarcoma. Random survival forest further indicated that, among the factors analyzed, peritoneal cytology status was second only to the International Federation of Gynecology and Obstetrics (FIGO) stage in terms of prognostic prediction. Finally, subgroup analyses substantiated the correlation between malignant peritoneal cytology and unfavorable overall survival in most subgroups.

CONCLUSIONS: Malignant peritoneal cytology status was an important prognostic factor complementing FIGO stage and was associated with a reduction in overall survival. Peritoneal cytology evaluation during hysterectomy may be recommended for prognosis estimation for uterine leiomyosarcoma and endometrial stromal sarcoma.