Is Peritoneal Cytology an Independent Prognostic Factor in Early-Stage Endometrial Cancer?

The prognostic significance of positive peritoneal cytology (PPC) in patients with early-stage endometrial cancer (Stage I/II) was disregarded by FIGO in 2009 classification, though FIGO recommends to collect peritoneal washings for cytology in all patients of endometrial carcinoma. To find out the association between positive peritoneal cytology and other prognostic factors of early-stage endometrial cancer and the influence of positive peritoneal cytology on survival of these patients. Primary objective—Association of positive peritoneal cytology with overall survival (OS) and disease-free survival (DFS). Secondary objective—Association of positive peritoneal cytology with other prognostic factors of early-stage endometrial cancer. Data were collected retrospectively from department of Gynecological oncology, Acharya Harihar Regional Cancer Center, Cuttack, India, between July 2009 and December 2017. Patients with stage I/II endometrial cancer who had undergone complete surgical staging procedure including pelvic lymphadenectomy were included. Comparison of pathological characteristics in patients with or without malignant cells in peritoneal cytology was done using univariate and multivariate analysis followed by survival analysis using Kaplan–Meier curves in these two groups, and the difference in survival was obtained by the log-rank test. Out of total 192 patients, 29 (15.1%) had positive peritoneal cytology. Among patients with positive peritoneal cytology, 27.6% patients had non-endometrioid histology like clear cell carcinoma and serous carcinoma of endometrium (P = 0.001). Similarly, 44.8% patients had Grade 3 histology, 51.7% patients had more than 50% myoinvasion, 48.3% patients had positive LVSI (lymphovascular space invasion) and 17.2% patients had stage II disease. Patients with positive peritoneal cytology had 17 months of lower disease-free survival (P < 0.0001) and 16 months of lower overall survival (P < 0.0004) compared to patients with negative peritoneal cytology. In multivariate analysis, positive peritoneal fluid cytology remained an independent prognostic factor for both disease-free survival (DFS) and overall survival (OS). Our study suggests that positive peritoneal cytology may be a potential prognostic factor in early-stage endometrial cancer owing to its significant association with other prognostic factors and its significant influence on both DFS (disease-free survival) and OS (overall survival).