Co-morbidities, socioeconomic status impact survival rates in colorectal cancer

Blacks are surviving colorectal cancer at a significantly lower rate compared to whites and Asians due to co-morbidities and their socioeconomic status, according to research by epidemiologists at The University of Texas Health Science Center at Houston (UTHealth).

Among the ethnic groups examined, Asians had the lowest risk of death. Whites had a 26 percent higher risk and blacks had a 56 percent higher risk of death compared to Asians. Socioeconomic status had the most significant impact on the survival rates of the three groups. The research is published in the July issue of Cancer, a peer-reviewed journal of the American Cancer Society (ACS).

"Co-morbidities and socioeconomic status appear to be important factors contributing to blacks' poorer survival relative to whites and Asians. However, substantial racial disparities in survival persisted," said lead author Arica White, Ph.D., M.P.H., former doctoral student at The University of Texas School of Public Health, part of UTHealth. "The results from this study will inform our progress toward eliminating health disparities and reducing the number of deaths from colorectal cancer."

Colorectal cancer is the third most frequently diagnosed non-skin cancer in men and women in the United States, according to the ACS. The risk of developing colorectal cancer is slightly higher in men than in women. ACS, which estimates that 51,000 Americans will die from colorectal cancer this year, recommends regular colorectal cancer screening or testing among the most important ways to prevent colorectal cancer.

According to White, this is the first study which compares factors that contribute to colorectal cancer survival differences between whites and other racial groups and between Asians and other racial groups. Also collaborating on the study were UTHealth School of Public Health researchers Sally W. Vernon, Ph.D., director of the Division of Health Promotion and Behavioral Sciences; Luisa Franzini, Ph.D., associate professor of management, policy and community health; and Xianglin L. Du, M.D., Ph.D., associate professor of epidemiology.

The study included more than 37,000 Medicare beneficiaries from across the United States who had been diagnosed with stages I to III colorectal cancer from 1992 to 2002. Investigators examined racial disparities in surviving colorectal cancer among whites, blacks and Asians based on differences in sociodemographic factors, tumor characteristics, stage at diagnosis, treatment and hospital characteristics.

"This research also sets the stage for future research to further examine the role of socioeconomic status and co-morbidities as well as other factors that have previously not been examined," said White. Some of the factors such as tumor characteristics and treatment appeared to substantially reduce the mortality difference between whites and blacks but did not have an impact on the mortality difference between Asians and blacks.

Lifestyle differences may also explain some of the dissimilarities in survival, according to White. Previous studies have revealed that obese patients have a 50 percent increased risk of developing colon cancer and a 30 percent higher risk of dying from the disease.

White noted that future research should examine the role of other factors such as quality of care, particularly treatment and post-treatment surveillance. White is currently an Epidemic Intelligence Service Officer at The Centers for Disease Control and Prevention.