A new study published in PLOS One offers one reason why African-American patients with colon cancer have poorer survival than Caucasian patients with the disease.
In a population-based, case-control study, John M. Carethers, MD, and colleagues evaluated 503 patients with colon cancer from the North Carolina Colon Cancer Study. Patient groups included in the study were 45% African-American and 55% Caucasian. Tissue samples taken at the time of surgery were assessed for various markers, including a genetic marker called microsatellite instability (MSI).
Research shows that MSI, while resistant to some chemotherapy, is linked to better outcomes in patients with colon cancer.
The researchers found that 14% of Caucasian patients had MSI colon cancer vs. 7% of African-American patients. They also noted that African-American patients were more likely to have cancer in the right side of their colon, which is more likely to be missed on screening. Right-sided cancer is also usually found when larger and more advanced, as compared with left-sided cancers.
Although drawing firm conclusions based upon one study is difficult, these results shed some light on why African-American patients with colon cancer may experience worse outcomes than Caucasian patients with the disease. Additionally, the researchers concluded that the data suggest more aggressive strategies may be needed to detect right-sided colon cancer.
African-Americans with colon cancer are half as likely as Caucasian patients to have a type of colon cancer that is linked to better outcomes. The finding may provide insight into why African-Americans are more likely to die of colon cancer than Caucasians with the same stage of disease.
The population-based study of 503 people with colon cancer found that 14% of Caucasians and 7% of African-Americans had a genetic marker called microsatellite instability, or MSI. These types of tumors are known to be resistant to the chemotherapy drug 5FU. Yet, even without chemotherapy, these patients tend to have better outcomes.