May 13 (HealthDay News) -- Even though black and white rectal cancer patients have similar referral rates to oncologists, blacks are less likely to receive chemotherapy or radiation therapy, new research shows.

In their study, researchers from the University of Michigan Comprehensive Cancer Center looked at 2,582 white patients and 134 black patients, aged 66 and older.

The study found that 75 percent of whites and 73 percent of blacks saw an oncologist after being diagnosed with rectal cancer, but only 54 percent of blacks received chemotherapy, compared with 70 percent of whites. In addition, rates of referral to a radiation oncologist were similar, but only 74 percent of blacks received radiation therapy, compared with 83 percent of whites.

The findings were published in the May 13 online issue of the Journal of the National Cancer Institute.

"Although there wasn't a discrepancy between African-Americans and whites in the rates of consultation with an oncologist, we found a large discrepancy in the receipt of chemotherapy. This is very important. We knew that African-Americans were not receiving chemotherapy for rectal cancer at the same rates as white Americans, and it was contributing to their increased mortality. Now we have a better idea of where the problem lies: somewhere between the visit with the oncologist and the actual initiation of chemotherapy," study author Dr. Arden Morris, an assistant professor of surgery at the U-M Medical School and chief of general surgery at the VA Ann Arbor Healthcare System, said in a prepared statement.

Compared to whites, blacks have as much as a 20 percent worse long-term survival rate after rectal cancer surgery. It's known that the use of chemotherapy and radiation improves survival in all rectal cancer patients by as much as 20 percent. It's believed that the lack of chemotherapy and radiation treatment in blacks is largely responsible for their lower long-term survival rates.

"We now know that the initial visit with an oncologist is not the barrier to treatment. Our next step is to better understand what are the human factors that contribute to this discrepancy. We're interested in hearing what individual people have to say," Morris said.

She and her colleagues suspect social differences and priorities among different groups -- such as patient preferences or access to resources such as transportation or family care -- may contribute to these discrepancies.

"Choice is important. If there's a choice, this maybe isn't a disparity but a preference. But if it's not a choice, then we need to understand the barriers and find solutions," Morris said.

In her next study, she plans to interview patients who've been treated for colorectal cancer to learn how they reached the decision to have chemotherapy or whether they feel they even made that decision themselves.

SOURCE: University of Michigan news release, May 13, 2008