Positive peritoneal cytology and its prognostic value in endometrioid adenocancer confined to the uterus

Trends in peritoneal cytology evaluation at hysterectomy for endometrial cancer in the United States

OBJECTIVE

The collection of a peritoneal cytologic sample at the time of surgery for endometrial cancer has traditionally been an important part of surgical staging. In 2009, the International Federation of Gynecology and Obstetrics revised the cancer staging schema for endometrial cancer and removed peritoneal cytology from the staging criteria. The current National Comprehensive Cancer Network guidelines and the International Federation of Gynecology and Obstetrics organization, however, recommend evaluation of peritoneal cytology at the time of hysterectomy. This study examined population-based trends, characteristics, and outcomes of peritoneal cytologic sampling for endometrial cancer surgery following the 2009 staging revision in the United States.

METHODS

This is a retrospective observational study querying the Surveillance, Epidemiology, and End Results Program to examine women with stage I-III endometrial cancer who underwent hysterectomy from 2010 to 2017. Trends, characteristics, and survival associated with peritoneal cytologic evaluation at the time of hysterectomy were assessed in multivariable analysis and with propensity score weighting.

RESULTS

Among 62,809 women who underwent hysterectomy, 43,873 (69.9%) had peritoneal cytologic evaluation at surgery and 18,936 (30.1%) did not. Utilization of peritoneal cytologic evaluation decreased from 75.5% to 64.9% during the study period (P < 0.001). In multivariable analysis, more recent year of surgery was independently associated with a decreased likelihood of performance of peritoneal cytology (adjusted-odds ratio of peritoneal cytology evaluation in 2017 versus 2010 0.56, 95% confidence interval [CI] 0.52-0.60). Peritoneal cytologic evaluation at the time of hysterectomy was associated with improved all-cause mortality (hazard ratio in the whole cohort 0.94, 95%CI 0.89-0.99; and hazard ratio in endometrioid histology 0.90, 95%CI 0.84-0.97).

CONCLUSION

Performance of peritoneal cytologic sampling has gradually decreased following the 2009 staging revision in the United States. Our study suggests that peritoneal cytology evaluation at hysterectomy may be associated with improved survival in certain tumor groups.

Malignant peritoneal cytology and increased mortality risk in stage I non-endometrioid endometrial cancer

OBJECTIVE

To examine the survival of women with stage I non-endometrioid endometrial cancer with malignant peritoneal cytology.

METHODS

A retrospective observational cohort study was conducted to examine the National Cancer Institute's Surveillance, Epidemiology, and End Results Program from 2010 to 2016. Women with stage I serous, clear cell, carcinosarcoma, undifferentiated, and mixed endometrial cancer with known peritoneal cytology results at hysterectomy were examined (N = 4506). Propensity score inverse probability of treatment weighting was used to balance the measured covariates, and survival outcomes were assessed according to peritoneal cytology results.

RESULTS

Malignant peritoneal cytology was reported in 401 (8.9%) women. In multivariable analysis, older age, serous histology, and large tumors were associated with an increased likelihood of malignant peritoneal cytology (all, P < 0.05). In a propensity score weighted model, malignant peritoneal cytology was associated with a nearly two-fold increase in all-cause mortality risk compared to negative peritoneal cytology (5-year rates, 63.4% versus 80.2%, hazard ratio 2.18, 95% confidence interval 1.78-2.66). In sensitivity analyses, malignant peritoneal cytology was associated with decreased overall survival in old and young age groups, serous, clear cell, carcinosarcoma, and mixed histology groups, stage T1a disease, and staged and unstaged cases, but not for stage T1b disease. Difference in 5-year overall survival rates between the malignant and negative peritoneal cytology groups was particularly large among those with clear cell histology (24.0%), stage T1a disease (19.4%), aged >78 years (18.2%), and serous tumors (17.6%).

CONCLUSION

Malignant peritoneal cytology can be prevalent in stage I non-endometrioid endometrial cancer. Our study suggests that malignant peritoneal cytology is a prognostic factor for decreased survival in stage I non-endometrioid endometrial cancer.

Malignant peritoneal cytology and decreased survival of women with stage I endometrioid endometrial cancer

BACKGROUND

To examine the association between malignant peritoneal cytology and survival in women with early-stage endometrioid endometrial cancer.

METHODS

This is a retrospective cohort study using the Surveillance, Epidemiology, and End Results Program from 2010 to 2016. Women with stage I endometrioid endometrial cancer who had peritoneal cytology testing at hysterectomy were examined (N = 24,800). Characteristics and survival related to malignant peritoneal cytology were assessed. The propensity score inverse probability of treatment weighting was used to balance the measured covariates.

FINDINGS

Malignant peritoneal cytology was reported in 1081 (4.4%) women. In multivariable analysis, stage IB disease and moderately/poorly differentiated tumours were associated with an increased likelihood of malignant peritoneal cytology (both P < 0.05). In a weighted model, malignant peritoneal cytology was associated with decreased cause-specific survival (5-year rates, 92.1% versus 96.8%, hazard ratio [HR] 1.98, 95% confidence interval [CI] 1.56-2.52) and overall survival (89.4% versus 93.1%, HR 1.41, 95% CI 1.16-1.72). In sensitivity analyses, malignant peritoneal cytology was associated with decreased overall survival in the high-intermediate-risk group (5-year rates, 77.8% versus 83.6%, HR 1.57, 95% CI 1.20-2.06) and decreased cause-specific survival in the low-risk group (95.4% versus 98.0%, HR 1.64, 95% CI 1.01-2.68). In the high-intermediate-risk group with malignant peritoneal cytology, postoperative chemotherapy was associated with improved overall survival compared to whole pelvic radiotherapy (5-year rates, 82.7% versus 64.6%, HR 0.36, 95% CI 0.14-0.96). This association was not observed in negative cytology cases (81.5% versus 79.7%, HR 0.78, 95% CI 0.53-1.14).

INTERPRETATION

Malignant peritoneal cytology may be associated with decreased survival in stage I endometrioid endometrial cancer.