Malignant peritoneal cytology was prognostic for women with stage II-III endometrial cancer, according to a retrospective review of the National Cancer Institute’s SEER programpublished in the Annals of Surgical Oncology.

Specifically, the benefit of adjuvant therapy differed depending on the status of peritoneal cytology, the study showed.

Researchers evaluated the treatment and outcomes of 7467 women with stage II-III endometrial cancer who underwent hysterectomy from 2010 to 2016. Of these women, 22.3% had malignant peritoneal cytology. According to the researchers, “This prevalence is far higher than in stage I endometrial cancer, where malignant peritoneal cytology is reported to be around 4–10%.”

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Malignant peritoneal cytology was associated with nonendometrioid histology, higher tumor stage, and nodal metastasis (P <.05).

A propensity score-weighted model showed that malignant peritoneal cytology was associated with a 35% increased risk for all-cause mortality compared with negative peritoneal cytology.

Chemotherapy alone (42.7%) was the most common adjuvant treatment followed by chemotherapy plus whole pelvic radiotherapy (40.0%) and radiotherapy alone (17.3%).

The researchers found that the type of adjuvant therapy varied based on histology and peritoneal cytology results. For example, in nonendometrioid histology, combination chemotherapy and whole pelvic radiotherapy were associated with improved overall survival compared with chemotherapy of whole pelvic radiotherapy alone regardless of the cytology results (P <.05).

However, among women with malignant peritoneal cytology, the combination of chemotherapy and whole pelvic radiotherapy was associated with improved overall survival (P =.026).

Based on these findings, the researchers made 3 recommendations. First, the collection of a peritoneal cytologic sample at the time of hysterectomy. Second, the recognition that malignant peritoneal cytology is a prognostic factor even in stage II-III disease. Third, that peritoneal cytology should be incorporated in treatment algorithms for adjuvant therapy.

Disclosures: Several study authors declared affiliations with the pharmaceutical industry. Please see the original article for a full list of authors’ disclosures.


Matsuo K, Matsuzaki S, Nusbaum DJ, et al. . Ann Surg Oncol. Published online April 1, 2021. doi:10.1245/s10434-021-0990-4