Significance of abnormal peritoneal cytology on survival of women with stage I–II endometrioid endometrial cancer

Abstract Objective To examine survival of women with stage I–II endometrioid endometrial cancer whose peritoneal cytology showed malignant or atypical cells (abnormal peritoneal cytology). Methods This is a multi-center retrospective study examining 1668 women with stage I–II endometrioid endometrial cancer who underwent primary hysterectomy with available peritoneal cytology results between 2000 and 2015. Abnormal peritoneal cytology was correlated to clinico-pathological characteristics and oncological outcome. Results Malignant and atypical cells were seen in 125 (7.5%) and 58 (3.5%) cases, respectively. On multivariate analysis, non-obesity, non-diabetes mellitus, cigarette use, and lympho-vascular space invasion were independently associated with abnormal peritoneal cytology (all, P P P =0.008) on multivariate analysis. Abnormal peritoneal cytology was significantly associated with increased risks of distant-recurrence (5-year rates: 8.8% versus 3.6%, P =0.001) but not local-recurrence (5.2% versus 3.0%, P =0.32) compared to negative cytology. Among women with stage I disease, abnormal peritoneal cytology was significantly associated with an increased risk of distant-recurrence in the low risk group (5-year rates: 5.5% versus 1.0%, P versus 10.8% P =0.60). Among 183 women who had abnormal peritoneal cytology, postoperative chemotherapy significantly reduced the rate of peritoneal recurrence (5-year rates: 1.3% versus 9.2%, P =0.039) whereas postoperative radiotherapy did not (7.1% versus 5.5%, P =0.63). Conclusion Our study suggests that abnormal peritoneal cytology may be a prognostic factor for decreased survival in women with stage I–II endometrioid endometrial cancer, particularly for low-risk group.