Research targets colorectal cancer disparity

A grandmother, two great-aunts and a cousin.

That’s how many people have been diagnosed with colorectal cancer in Dr. Jason Willis’ family.

The MD Anderson Cancer Center oncologist has seen the pain it can cause. As the child of a Latino mother and a Black father, he is deeply familiar with the increased cancer risk for people of color.

“It’s striking to see not only the rates of early onset colon cancer increase over the past several years but also this disparity,” he said. “Certainly as a Black man, that jumps out to me.”

Willis’ personal history drives his research into what makes the disease disproportionately prevalent and deadly for Black people. Inequities in access to health care are a factor, he said. But Willis has been working with a team of researchers to illuminate a different question: Is there a genetic explanation?

“Even if you adjust for the fact that there are some differences across access to care, and even if you adjust for the stage of diagnosis, we see differences in terms of survival,” he said.

Colorectal cancer is the third-most common cancer in men and the secondmost common in women, according to the National Institutes of Health. It’s also the second-most common cause of cancer death in the U.S. More than 52,000 people are expected to die from the disease this year, according to the American Cancer Society.

An NIH study published in 2017, which analyzed data from cancer registries across the U.S., found that five-year survival rates for colorectal cancer were 10 percent lower for Black patients than for white patients.

Another NIH study, from 2016, said Black patients tend to develop colorectal cancer at an earlier age and are more likely to have a deadlier type of colon cancer.

For his research, Willis is sequencing the DNA of more than 100 colorectal cancer patients who were treated at Lyndon B. Johnson Hospital in Houston over the last several years. The majority are people of color, and his findings will be compared with the largely white patient population at MD Anderson, he said.

He is focused on understanding both the inherited risk factors and non-hereditary genetic mutations.

Most genetic studies of colorectal cancer have focused on people of European ancestry, Willis said.

“There’s been a more recent effort to expand those studies to find out … are there perhaps unique hereditary factors in African Americans that we haven’t discovered yet?” he said.

Willis’ work is important to provide a “360-degree” view of the problem, said Dr. Farhaan Vahidy, associate director of the Center for Outcomes Research at Houston Methodist system. It involves socioeconomic factors such as inadequate housing, food insecurity and lack of transportation.

“I think the solution does not lie in one aspect,” Vahidy said. “It’s probably going to be an interaction of these different factors.”

Willis’ project is part of an initiative at MD Anderson to understand racial disparities in cancer.