Tumor stage at diagnosis differed based on race among military beneficiaries

Enewold L. Cancer. 2011;doi:10.1002/cncr.26208.

Racial disparities in tumor stage at diagnosis were observed among older nonactive duty beneficiaries but not among active duty beneficiaries in a study evaluating data from the Department of Defense Military Health System.

Tumor stage at diagnosis often differs based on racial or ethnic group, and some have attributed this to inequalities in health care access. Researchers set out to determine whether tumor stage at diagnosis differed between blacks and whites in the Department of Defense (DoD) Automated Cancer Tumor Registry, a system in which beneficiaries have equal access to health care. They chose to evaluate patients with breast, cervical, colorectal or prostate cancer, because effective screening methods exist for each. Data were from 1990 to 2003.

The researchers found no significant differences in tumor stage distribution between black and white active duty beneficiaries. They did, however, find significant differences among both men and women who were nonactive duty beneficiaries.

This difference persisted among breast and prostate cancers after adjustment for age, marital status, year of diagnosis, military service branch, geographic region and tumor grade. After adjustment, white women aged older than 49 years were less likely to have nonlocalized breast cancers than black women in this age group. This difference increased with age: An odds ratio of 1.07 among the 18- to 39-year-old age group increased to 0.63 among women aged 65 years or older.

Also after adjustment, among men with prostate cancer, the researchers observed a significant difference in tumor stage for those aged 65 years or older. However, they noted that the actual variation in distribution was small, which suggests that statistical significance may have been the result of a large sample size.

Compared with the general population, racial differences in the percentage of cancers that were localized among nonactive duty beneficiaries were similar or slightly lower.

“The distribution of tumor stage by race did not appear to vary greatly among active duty beneficiaries … but small sample sizes may have resulted in insufficient power to detect true differences,” the researchers wrote. “Although the DoD system is based on equal access, racial variation in socioeconomic status and supplemental insurance still may affect tumor stage at diagnosis. Therefore, more studies are needed to assess the independent impact of these and other possible factors.”

Charles L. Shapiro, MD
Charles L. Shapiro

Higher-stage cancers are diagnosed in blacks vs. whites. The possible reasons include unequal access to health care screening, risk perceptions or biological differences in the cancers that develop in these groups. Do these results contribute to answering questions of access to care and biological differences as explanations for the observed racial discrepancy in this study and prior studies? If the older nonactive duty military personnel exclusively used military health systems to get their cancer screenings, you might expect that this would in part solve the access-to-care part. The fact that these differences still exist may mean that risk perceptions, biological factors, both or as yet some unknown factor(s) contribute to racial disparities in stages at which cancers are diagnosed. However, it was not possible to provide data on actual screening practices or to seek screening at nonmilitary facilities. Given these caveats, the longstanding questions of why cancers are diagnosed at early/later stages depending on race go largely unanswered, and in my opinion, this study has only limited impact on clinicians or screening practices.

– Charles L. Shapiro, MD

Professor of Medicine, Director of Breast Medical Oncology, Ohio State Medical Center and James Cancer Hospital, Columbus, Ohio

Disclosure: Dr. Shapiro reports no relevant financial disclosures.

Follow HemOncToday.com on Twitter.