The new study, which appears in the March issue of Cancer Causes and Control, examined the effect of race on colorectal cancer outcomes in elderly Tennesseans with identical health care coverage and provided some revealing results.
The colon cancer death rate in blacks is disproportionately higher than in whites. These disparities prevail even when factors like age, gender, stage of cancer, and geography are taken into consideration.
"In many, if not all cancers, there are racial disparities in survival," said Walter Smalley, M.D., associate professor of Medicine at Vanderbilt University Medical Center and section chief of Gastroenterology at the Nashville Veteran's Administration Medical Center. "Colon cancer, which is the No. 2 cancer killer in America, is no exception."
Several previous studies have demonstrated a racial difference in colon cancer survival. A 1998 study from the Surveillance Epidemiology End Results program found that the five-year survival rate for patients with localized colorectal cancer (stages 1 and 2) in whites was 90 percent compared to 83 percent for blacks.
For patients with a regional spread of the cancer (stages 3 and 4), survival statistics were similarly disproportionate: 65 percent in whites and 53 percent in blacks. Studies of Medicare recipients have also demonstrated the survival disparity, but the level of care among those patients is highly variable, making interpretation difficult.
One of the first indications that the disparity could be countered by equal access to health care came from a nationwide study of colon cancer patients treated at VA Medical Centers. The study found that both the processes of care and overall survival were essentially the same for both blacks and whites in the VA system. Since most study participants were male, the findings may be limited in their applicability to the general population.
"Studies of Medicare recipients alone have shown that this racial disparity persists, but to this point no one has looked at [patients with combined Medicare and Medicaid coverage]," Smalley said. "So what makes this study unique is that everybody in the study has exactly the same insurance status."
The researchers reviewed the medical records of 949 elderly patients diagnosed with colon or rectal cancer between 1984 and 1992. They tracked the patients' progress through 1999.
All were Medicare and Medicaid patients from the beginning of their illness throughout the study.
"These patients were civilians from every county in Tennessee," said Smalley, making the study more generalized to a wider population than if conducted at a single medical center.
"The bottom line is, we found that there were no racial differences in survival," Smalley said. "There were subtle differences in how patients were treated. For example, whites were slightly more likely than blacks to receive surgical therapy, and blacks were more likely to be treated with radiation therapy for rectal cancer.
"Our contention is that while there may be biological differences between African-Americans and whites and we know that there are differences in how they are treated, the fact is that we are likely to overcome a lot of those differences if everyone has equal access to care."
The primary author of the study, Selwyn Rogers Jr., M.D., formerly at Meharry Medical College, added, "these findings argue that the processes of care may be similar for patients with identical insurance."
Rogers, an assistant professor of Surgery at Harvard Medical School and section chief of Trauma, Burns, and Surgical Critical Care at the Brigham and Women's Hospital in Boston, is optimistic that this research lays the foundation to eliminate this disparity.
"Further work to define optimal processes of care and apply those processes universally would eliminate health care disparities," Rogers said.
Rogers continues to investigate the processes that impact patient care in a large multi-center study sponsored by the National Cancer Institute.
Wayne Ray, Ph.D., professor of Preventive Medicine and director of the division of Pharmaco-epidemiology at VUMC, was a co-author of the paper. The research was supported by the Agency for Healthcare Research and Quality, Centers for Education and Research on Therapeutics through a cooperative agreement.
by Melissa Marino
Journal
Cancer Causes & Control