Cleaved caspase-3 expression is a potential prognostic factor for endometrial cancer with positive peritoneal cytology

Introduction Positive peritoneal cytology (PPC) in endometrial cancer remains a controversial topic. Cleaved caspase-3 (CC3) and Ki-67 are excellent markers of apoptotic and proliferating cells, respectively. The objective of this study was to determine the significance of CC3 and Ki-67 expression in peritoneal cytology samples as prognostic factors for endometrial cancer with PPC. Methods Sixty endometrial cancer specimens with PPC alone were divided into 51 endometrioid tumours (43 endometrioid carcinomas and eight carcinomas with squamous differentiation) and nine non-endometrioid tumours (two serous carcinomas, three clear cell carcinomas and four carcinosarcomas). CC3 and Ki-67 expression in peritoneal cytology samples were immunocytochemically assessed and correlated with disease-free survival (DFS) and overall survival (OS). Results Expression levels of CC3 and Ki-67 were not associated with any clinicopathological parameter. Patients with non-endometrioid tumours had significantly shorter DFS (P = .001) and OS (P = .001). Low CC3 expression (CC3Low ) was significantly associated with shorter OS (P = .02), but not DFS (P = .13). Multivariate analysis showed that non-endometrioid histology and CC3Low were independent prognostic factors. However, Ki-67 expression was not associated with survival. When endometrioid and non-endometrioid tumours were assessed separately, CC3Low was significantly associated with shorter DFS (P = .002) and OS (P = .002) in patients with non-endometrioid tumours. Conclusions Our results suggest that CC3Low in peritoneal cytology samples is a poor prognostic factor in patients with endometrial cancers, especially non-endometrioid tumours. Immunocytochemical analysis of CC3 expression could potentially facilitate identification of patients with high-risk endometrial cancer with PPC.