Receipt of adjuvant endometrial cancer treatment according to race: an NRG Oncology/Gynecologic Oncology Group 210 Study

Background: Black women with endometrial cancer are more likely to die of their disease compared with white women with endometrial cancer. These survival disparities persist even when disproportionately worse tumor characteristics among black women are accounted. Receipt of less complete adjuvant treatment among black patients with endometrial cancer could contribute to this disparity.

Objective: We assessed the hypothesis that black women with endometrial cancer are less likely than their white counterparts to receive adjuvant treatment within subgroups defined by tumor characteristics in the NRG Oncology/Gynecology Oncology Group 210 Study.

Study design: Our analysis included 615 black and 4283 white women with endometrial cancer who underwent hysterectomy. Women completed a questionnaire that assessed race and endometrial cancer risk factors. Tumor characteristics were available from pathology reports and central review. We categorized women as low-, intermediate-, or high-risk based on the European Society for Medical Oncology definition. Adjuvant treatment was documented during postoperative visits and was categorized as no adjuvant treatment (54.3%), radiotherapy only (16.5%), chemotherapy only (15.2%), and radiotherapy plus chemotherapy (14.0%). We used polytomous logistic regression to estimate odds ratios and 95% confidence intervals for multivariable-adjusted associations between race and adjuvant treatment in the overall study population and stratified by tumor subtype, stage, or European Society for Medical Oncology risk category.

Results: Overall, black women were more likely to have received chemotherapy only (odds ratio, 1.40; 95% confidence interval, 1.04-1.86) or radiotherapy plus chemotherapy (odds ratio, 2.01; 95% confidence interval, 1.54-2.62) compared with white women in multivariable-adjusted models. No racial difference in the receipt of radiotherapy only was observed. In tumor subtype-stratified models, black women had higher odds of receiving radiotherapy plus chemotherapy than white women when diagnosed with low-grade endometrioid (odds ratio, 2.04; 95% confidence interval, 1.06-3.93) or serous tumors (odds ratio, 1.81; 95% confidence interval, 1.07-3.08). Race was not associated with adjuvant treatment among women who had been diagnosed with other tumor subtypes. In stage-stratified models, we observed no racial differences in the receipt of adjuvant treatment. In models that were stratified by European Society for Medical Oncology risk group, black women with high-risk cancer were more likely to receive radiotherapy plus chemotherapy compared with white women (odds ratio, 1.41; 95% confidence interval, 1.03-1.94).

Conclusion: Contrary to our hypothesis, we observed higher odds of specific adjuvant treatment regimens among black women as compared with white women within specific subgroups of endometrial cancer characteristics.