Black people with advanced colon cancer are less likely to get consultations with specialists and treatment with complex medicines than white people, according to a new study.

Those treatment differences may explain why black patients with the disease are 15 percent more likely to die than their white counterparts, researchers suggest.

“This disparity in treatment does result in survival differences that are quite substantial,” Dr. James Murphy told Reuters Health.

Murphy is the study’s senior author and an assistant professor in the Department of Radiation Medicine and Applied Sciences at the University of California, San Diego.

Colon cancer is the second leading cause of cancer death in the U.S., Murphy and his colleagues write in the Journal of the National Cancer Institute.

Previous studies have found black people are more likely to develop colon cancer, have more advanced cancer when diagnosed and are more likely to die of the disease than patients of other races.

For the new study, the researchers used data on 9,935 white and 1,281 black patients with late-stage colon cancer from a national database.

All of the patients were at least 66 years old and were diagnosed between 2000 and 2007. The study followed them until they died or through 2009.

Almost three-quarters of the patients had surgery to remove tumors from their colon or rectum and 5 percent also had surgery to remove tumors that had spread to their liver or lungs.

Half of the patients received chemotherapy and 13 percent received radiation.

Compared to whites, black patients were 10 percent less likely to undergo surgery to remove their original tumors and 40 percent less likely to have liver or lung procedures. They were also 17 percent less likely to get chemotherapy and 30 percent less likely to get radiation.

White patients lived - on average - a little more than six months after being diagnosed. That compared to less than five months among black patients.

Overall, 95 percent of the patients died during the study period. But the researchers found black patients were still 15 percent more likely to die than white patients.

To help determine why that was the case, the researchers tried to account for differences between the patients and their tumors. That only explained some of that 15 percent.

After adjusting the numbers for the differences in treatment, however, the increased risk of death among black patients disappeared, according to the researchers.

“The findings are consistent with a lot of other findings in the cancer care literature,” Sam Harper told Reuters Health. “We do see notable racial differences in survival and some of these do seem to be explained by differences in demographic factors and treatment differences.”

Harper was not involved with the study but has researched racial disparities in cancer care as an assistant professor at McGill University in Montreal.

Murphy added, however, that his team’s study cannot explain why the differences in treatment exist.

Differences in healthcare access, doctor biases and patient mistrust could play a role.

“I think the take-home point is that we need more research into treatment barriers to see how they can be overcome,” Murphy said.

Harper agreed that more research is needed into why black patients and white patients have different treatment experiences.

“I think this continues to be an important question to focus on,” he said.

Murphy said it’s hard to know what patients can do to make sure they don’t fall into the disparity gap.

“I think for providers just understanding that there is a disparity out there may make them aware and help reduce the disparity,” he said. “But we do need more research to identify individual barriers.”

SOURCE: Journal of the National Cancer Institute, online November 14, 2013.

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