SGO: Biology Role Cited for Racial Disparities in Uterine Cancer Outcomes

By Charles Bankhead
TAMPA, Fla., March 13 -- Blacks with uterine cancers have an increased risk for death and recurrence, even when they receive the same level of care as white women, suggested two studies reported here.Review of a government database revealed a 54% increased mortality risk for blacks after adjustment for all known prognostic factors, Jason D. Wright, M.D., of Columbia University, said at the Society of Gynecologic Oncologists meeting."There tends to be a difference in the type of tumors that African-American women have compared to Caucasian women," said Dr. Wright. "But even when adjusting for that, it doesn't completely explain the survival difference we're seeing.
"That suggests to us that there is probably some intrinsic difference in the tumors in African-American women that is causing this worse survival."
In the other study, there was an 11-fold higher risk of recurrence in black versus white women with stage I endometrial cancer, despite enrollment in a clinical trial that employed uniform standards of care, reported by George Maxwell, M.D., of Walter Reed Army Medical Center in Washington.
Black women with endometrial cancer have poorer outcomes compared with other racial and ethnic groups, a difference often attributed to disparities in access to healthcare services and in process of care. Whether biologic factors contribute to the outcome differences has remained unclear, said Dr. Wright.
Continuing the examination of outcome differences, investigators reviewed data from the Surveillance, Epidemiology, and End Results (SEER) program. The review identified 76,953 new cases of invasive uterine cancer from 1988 to 2004. The total included 66,829 white women, 4,940 black women, and 5,184 women of other racial and ethnic groups.
A comparison of histologic findings showed that 89% of white women had endometroid tumors, 9% had sarcomas, and 2% had serous/clear cell cancer. Among black women, endometrioid tumors accounted for 70% all the cancers, whereas sarcomas made up 26% of the total and serous/clear cell 4% (P<0.0001).
Black women also had a higher proportion of advanced-stage (III-IV) tumors at diagnosis, 26% versus 15% for white patients, Dr. Wright reported.
Examination of the care patients received showed that 22% of white women and 23% of black women had adjuvant radiation therapy, and 40% of both racial groups had lymphadenectomy.
In a multivariate analysis, after adjusting for all other known prognostic factors including stage and histology, black women had a relative risk of mortality of 1.54 compared with white women (95% CI 1.4 to 1.6).
Dr. Maxwell presented data from a retrospective review of a Gynecologic Oncology Group clinical trial of postoperative estrogen replacement therapy in women with stage I-II endometrial cancer. The trial included 110 black patients and 1,049 white patients. The primary endpoint was recurrence-free survival.
The analysis showed a significantly increased risk of recurrence in blacks randomized to estrogen-replacement therapy. Dr. Maxwell said five of 56 black patients in the estrogen-replacement therapy arm had recurrent disease compared with eight of 521 white patients. The difference translated into a relative risk of 11.2 for black versus white women (95% CI 2.86 to 43.59, P=0.0005).
Mortality data also revealed an increased hazard for black patients. After adjustment for age, body mass index, and tumor grade, black women had a relative risk of mortality of 2.24 (95% CI 1.01 to 4.94, P=0.047).
Subgroup analysis indicated the disparity in recurrence-free survival was limited to the estrogen-replacement therapy group, wherein black patients had an adjusted risk of 3.00 versus white patients (95% CI 1.06 to 8.50, P=0.038).
Neither Dr. Wright nor Dr. Maxwell reported relevant conflicts.
Primary source: Society of Gynecologic OncologistsSource reference:Wright JD, et al "Racial disparities in the patterns of care and outcome for uterine neoplasms" Gynecol Oncol 2008; 108(suppl 1):S30. Abstract 65. Additional source: Society of Gynecologic OncologistsSource reference: Maxwell G, et al "Racial disparities in recurrence among patients with early-stage endometrial cancer: A Gynecologic Oncology Group study" Gynecol Oncol 2008; 108(suppl 1):S30. Abstract 66.