Peritoneal cytology: a risk factor of recurrence for non-endometrioid endometrial cancer

Objective: We compared the impact of positive peritoneal cytology on prognosis between patients with endometrioid and non-endometrioid endometrial carcinoma.

Methods: We retrospectively reviewed the medical records of 490 patients diagnosed with endometrial cancer between 2000 and 2012. These patients were divided into two groups: endometrioid and non-endometrioid histologies. We compared the patients' baseline characteristics, tumor recurrence patterns, and survival to determine the prognostic factors and how they differed between the two groups.

Results: Of the included patients, 448 had endometrioid histology and 42 had non-endometrioid histology. A total of 27 patients experienced tumor recurrence: 17 with endometrioid histology (4.0%) and 10 with non-endometrioid histology (23.8%). Compared to endometrioid type, non-endometrioid type exhibited higher rates of recurrence (p<0.01). Recurrence sites of the non-endometrioid group were mainly peritoneal seeding (p<0.01) and distant organ metastasis (p=0.02). Risk factors for tumor recurrence included patient age, stage of disease, and adjuvant treatment for endometrioid type. On the other hand, in cases of non-endometrioid endometrial cancer, positive peritoneal cytology was an independent prognostic factor regardless of tumor stage (HR, 15.34; 95% CI, 3.55-66.25; p<0.01). Among cases with non-endometrioid histology, median recurrence-free survival significantly differed between the negative peritoneal cytology group and the positive peritoneal cytology group (120 months versus 22 months, respectively; p<0.01).

Conclusions: Positive peritoneal cytology is an independent prognostic factor for patients with non-endometrioid endometrial cancer.