The MD Anderson Cancer Center oncologist has seen the pain it can inflict both inside and outside the clinical setting. And as someone who is biracial, with a Hispanic mother and Black father, he is deeply familiar with the increased risk among 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 so disproportionately prevalent and deadly for the Black community compared to the white population. Structural racism that impedes access to healthcare is a major factor, he said. But Willis has been working with a team of researchers to illuminate another piece of that 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 diagnosed in men and the second-most 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., with more than 52,000 people expected to die from the disease this year, according to the American Cancer Society.

Black patients bear the heaviest burden, with higher rates of diagnoses and death compared to all other races. An NIH study published in 2017, which analyzed data from cancer registries across the U.S., found that 5-year survival rates for colorectal cancer were 10 percent lower for Black patients compared to white patients. Another NIH study, from 2016, said Black patients tend to develop colorectal cancer at a younger age and are more likely to have “proximal cancers,” or a type of colon cancer associated with higher death rates.

“This raises the possibility of higher genetic predisposition to (colorectal cancer) among African Americans and this has not been well studied,” the authors noted.

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

He is focused on understanding both the inherited risk factors passed down through generations, as well as genetic mutations that aren’t passed down. Early studies suggest that among Black Americans, certain mutations in the tumor may be affecting how cells accumulate and repair damage, allowing the cancer to grow faster. There is also a dearth of information on how much hereditary risk factors play a role.

Most genetic studies into colorectal cancer have lacked racial representation, he said, with much of that work focused on people with European ancestry.

“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 to tailor specific treatments and interventions, said Dr. Farhaan Vahidy, associate director of the Center for Outcomes Research at Houston Methodist system.

It’s a multi-faceted issue, he said, only to be fully understood by accounting for socioeconomic factors, such as inadequate housing, food insecurity, lack of transportation and other components that affect health.

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

Willis’ project, funded through a grant intended for underrepresented researchers, is part of a broader initiative at MD Anderson to illuminate the racial disparities in different types of cancer. Dr. Lorna McNeill, professor and chair in MD Anderson’s Department of Health Disparities, said data has shown for years that communities of color face poorer cancer outcomes.

But events over the last two years, including the COVID-19 pandemic and the murder in police custody of George Floyd, have energized national efforts to better understand health inequities.

“The NIH and other philanthropic organizations — everyone — has taken more interest in what is causing these disparities,” she said.