For both black men and women, cancers of the colon and rectum are the third most common cause of cancer deaths, according to the American Cancer Society. Additionally, death rates for cancer of the colon and rectum among blacks are about 30 percent higher than among whites, and more than two times higher than for Asian Americans, Pacific Islanders, American Indians, and Hispanics.
Several reasons have been suggested to explain these differences, including diagnosis at a later stage of disease, having more aggressive disease and having less access to screening tests for earlier diagnosis. Results of a multicenter study in the United States and Canada point to another possibility: response differences among blacks to standard chemotherapy treatments for advanced colorectal cancer.
The results also suggest that genetic differences in metabolism of chemotherapy drugs may play a role.
"The aim of this research was to compare African American with Caucasian patients with respect to responses, to the time it took for their cancers to become worse, and their overall survival. We also wanted to see if there was any difference in the side effects profile," said Dr. Richard M. Goldberg, professor of medicine and hematology-oncology division chief at the University of North Carolina at Chapel Hill and associate director of clinical research at UNC Lineberger Comprehensive Cancer Center.
Patients in the study donated a tube of blood for DNA studies. "We were looking at their DNA, focusing on minor differences called polymorphisms, or variations in DNA sequences that are present in specific genes in every cell in the patient's body," Goldberg said. "The genes that we were particularly interested in are those genes coding for key enzymes involved in dru
Contact: L.H. Lang
University of North Carolina School of Medicine