WASHINGTON -- Black women with advanced or recurrent endometrial cancer had significantly worse overall survival than white women who received the same therapy in four clinical trials.
WASHINGTON, Sept. 22 -- Black women with advanced or recurrent endometrial cancer had significantly worse survival duration than white women who received the same therapy in four clinical trials, reported several investigators.
Black women survived an average of 10.6 months, compared with 12.2 months for white women. Although black women overall had more serious disease at presentation, the differences in survival persisted even after controlling for variables that could affect clinical outcomes, wrote G. Larry Mitchell, M.D., of the Walter Reed Army Medical Center here, and colleagues in the Gynecologic Oncology Group.
"Although the causes of this survival difference remain to be elucidated, socioeconomic, biologic, and cultural etiologies may be involved," the investigators wrote in an early online article scheduled for publication in the Nov. 1 issue of Cancer.
According to American Cancer Society estimates, about 7% of women newly diagnosed with endometrial cancer are black, but black women account for about 14% of the approximately 7,000 deaths from the disease.
"The cause of racial disparity in endometrial cancer survival is multifactorial and may be related to the response of black women to medical illness, their use of health care resources, or interracial patient-physician communication," the authors wrote. "Racial differences in the type of care received also have been reported in population-based studies of endometrial cancer, suggesting that unequal treatment also may contribute to the gap in survival between black women and white women suffering from this disease."
Genetics may also play a role, they added, pointing to evidence that black women with endometrial cancer tend to present with undifferentiated and advanced-stage disease at the time of diagnosis, suggesting the presence of a more aggressive phenotype.
The investigators conducted a retrospective review of data on 169 black women and 982 white women with Stage III, Stage IV, or recurrent endometrial carcinoma who were participants in one of four different Gynecologic Oncology Group treatment trials. The trials compared Adriamycin (doxorubicin) alone or combined with Taxol (paclitaxel) and/or Platinol (cisplatin).
The author sifted through data on demographics, tumor histology, treatments, and outcomes to estimate survival, and performed between group comparisons.
In a pooled-data analysis, they found that black women were significantly more likely to have tumors with papillary serous histology, stage IV disease, and higher tumor grade than white women (P for all <0.001). The performance status of black women was also significantly worse than that of white women (P=0.018), even though the median age was similar between the groups.
Black women received the same chemotherapy regimens as white women, and although fewer black women than white had previously undergone radiation therapy (43% versus 57%, respectively) the difference was accounted for by the higher prevalence or recurrent disease among white women, the authors found. When they looked at radiation therapy rates only among women with recurrent disease, they found then to be comparable.
Women of both races had also undergone hysterectomy before study entry in equal numbers.
In multivariate analysis, the investigators found that factors predicting worse overall survival included stage IV disease (hazard ratio 1.52; 95% confidence interval , 1.16-2.00) and recurrent disease (hazard ratio 1.73, 95% CI, 1.34-2.24) compared with stage III disease; grade 2 and 3 tumors compared with grade 1 tumors (hazard ratio 1.29, 95% CI, 1.07-1.57 for grade 3 tumors, and 1.32; 95% CI, 1.09-1.60 for grade 2 tumors, P=0.025).
Other factors predicting worse survival were histology (clear cell histology but not papillary serous histology compared with endometrioid cell type), and lack of hysterectomy before study entry (hazard ratio for hysterectomy 0.77; 95% CI, 0.65-0.92). Radiotherapy prior to study entry was not, however, significantly associated with survival,
The last factor predicting survival was race. Before controlling for controlling for all other factors, black women with advanced or recurrent endometrial cancer had a 35% increased risk of death compared with white women. And after adjustment for clinical and treatment factors, the relative hazard ratio for death among black women was still significant, at 1.26 (95% CI, 1.06-1.51, P=0.010).
The authors did not observe any interactions between race and disease stage, histology, or tumor grade, indicating that the racial disparity was consistent across the clinical or pathologic spectra, they noted.
"Racial disparities research should continue to look for those features that are associated with a poor prognosis among minorities as a more effective means of identifying individuals who may benefit from alternative prevention and treatment strategies," Dr. Maxwell and colleagues wrote.
"We must attempt to improve our understanding of this phenomenon, particularly because current Census data suggest that the black population is expected to nearly double from its current size to 61 million individuals by the Year 2050," the authors concluded.