Steve Martinez, assistant professor of surgery at UC Davis Cancer Center, determined that while Hispanic and African-American women with advanced breast cancer are less likely to receive radiation therapy than their white counterparts, only African Americans have poorer outcomes than white patients with the same stage disease.
The findings, presented today in Washington, D.C., at the Association for Clinical Research Training and the Society for Clinical and Translational Science meeting, suggest that the lack of radiation therapy treatment is not responsible for the poorer survival noted among African-American patients.
“Is this a biological difference?” Martinez asks. “Do black patients benefit from post-surgery radiation therapy to the degree that Hispanics and whites benefit?”
These questions are part of Martinez’ ongoing exploration of cancer health disparities as they affect patients’ response to therapy and overall survival. A surgical oncologist, Martinez is one of many clinicians at UC Davis Cancer Center who also are finding ways to address the disproportionate cancer burden for certain patient populations.
The current study is one of two Martinez undertook to examine factors influencing survival for breast cancer patients. In the first, he looked at data from more than 12,000 women from throughout the country who had breast cancer that had spread to 10 or more lymph nodes and that had resulted in either lumpectomy or mastectomy.
“By definition, all of these patients should get radiation therapy,” he said.
What he found was that Hispanic patients were 20 percent less likely to get radiation therapy than their white counterparts, and black patients were about 24 percent less likely to receive radiation therapy.
For the second study, he wanted to learn whether the disparities in receipt of radiation therapy resulted in poorer outcomes for Hispanic and African-American women.
“That is not what we found,” he said. “Hispanic patients were not significantly different from white patients in overall survival rates, but black patients did worse. This survival disparity seen in black patients was unrelated to whether or not they received radiation therapy as part of their treatment.”
Martinez examined 10-year survival rates in patients from each group who received radiation therapy and those who did not. While he found dramatic differences in survival for white women who had radiation therapy (an 11 percent survival boost), black patients had just a 3 percent difference in their survival rates.
Martinez plans to continue his research into factors that may influence whether or not patients receive radiation therapy and that may also affect their outcomes, including possible biological differences.
“We are trying to see which treatments work best for which people,” he said. “Ultimately, we can figure out treatments that may work well for you, but not for someone else. This is a step on that path.”
UC Davis Cancer Center is a National Cancer Institute-designated cancer center that cares for 9,000 adults and children with cancer each year from throughout the Central Valley and inland Northern California. Its Outreach Research and Education Program works to eliminate ethnic disparities in cancer region-wide.