Abstract
BACKGROUND: Few studies have analyzed relationships between risk factors for endometrial cancer, especially with regard to aggressive (non-endometrioid) histologic subtypes, and prognosis. We examined these relationships in the prospective NRG Oncology/Gynecologic Oncology Group 210 trial. METHODS: Prior to surgery, participants completed a questionnaire assessing risk factors for gynecologic cancers. Pathology data were derived from clinical reports and central review. We used the Fine and Gray subdistribution hazards model to estimate subhazard ratios (HRs) and 95% confidence intervals (CIs) for associations between etiologic factors and cause-specific subhazards in the presence of competing risks. These models were stratified by tumor subtype and adjusted for stage and socioeconomic status indicators. RESULTS: Median follow-up was 60months after enrollment (range: 1day-118months). Among 4609 participants, a total of 854 deaths occurred, of which, 582 deaths were attributed to endometrial carcinoma. Among low-grade endometrioid cases, endometrial carcinoma-specific subhazards were significantly associated with age at diagnosis (HR=1.04, 95% CI=1.01-1.06 per year, P-trend) and BMI (class II obesity vs. normal BMI: HR=2.29, 95% CI=1.06-4.98, P-trend=0.01). Among high-grade endometrioid cases, endometrial carcinoma-specific subhazards were associated with age at diagnosis (HR=1.05, 95% CI=1.02-1.07 per year, P-trend<0.001). Among non-endometrioid cases, endometrial carcinoma-specific subhazards were associated with parity relative to nulliparity among serous (HR=0.55, 95% CI=0.36-0.82) and carcinosarcoma cases (HR=2.01, 95% CI=1.00-4.05). DISCUSSION: Several endometrial carcinoma risk factors are associated with prognosis, which occurs in a tumor-subtype specific context. If confirmed, these results would suggest that factors beyond histopathologic features and stage are related to prognosis. ClinicalTrials.gov Identifier: NCT00340808.