Racial Disparities in Cancer Enter the Spotlight

July 29, 2020

Underrepresentation of blacks in clinical trials is garnering special attention.

In 1968, the Kerner Commission concluded: “Our nation is moving toward two societies, one black, one white — separate and unequal.”

In many ways, cancer in this country — its incidence, prevalence, treatment access and outcomes — also is riven by race, with black Americans faring worse than whites.

Blacks “have the highest death rate and shortest survival of any racial/ethnic group in the U.S. for most cancers,” according to the 2019-2021 American Cancer Society’s Cancer Facts & Figures for African Americans. Recognition of racial disparities in cancer is not new, and the many questions about disparities have not gone unexamined. A PubMed search of “racial disparity cancer” brings up 1,906 results for just the past five years. A similar keyword search of the abstracts presented at the 2020 meeting of the American Society of Clinical Oncology (ASCO) in May brought up 22 abstracts. The National Cancer Institute has a Center to Reduce Cancer Health Disparities, and its Surveillance, Epidemiology and End Results database is easily searchable by race. The cancer society has been publishing its biannual facts and figures reports about African Americans’ health for at least 15 years.

But Americans now are seeing a wide range of issues through the lens of race and racism like never before, and racial disparities in cancer have gained new salience. There’s evidence of fresh interest and commitment on the part of prominent cancer research groups and pharmaceutical companies. As part of a virtual meeting in late June, the American Association for Cancer Research held a panel discussion titled “Racism and Racial Inequities in Cancer Research,” led by the organization’s president, Antoni Ribas, M.D., Ph.D., FAACR. When the discussion turned to the underrepresentation of African Americans in cancer clinical trials, Ken Frazier, CEO of Merck, acknowledged that “too often we go to the usual suspects — the academic medical centers that we are very used to using.” Frazier promised to work with the FDA and others “to make sure that this isn’t just something that has enormous rhetorical appeal but happens in reality.”

Black-white differences

Fifty years ago, the overall cancer death rate was lower among blacks than among whites. But since the 1960s, the death rate of black Americans has been higher than that of whites, according to the American Cancer Society report. When all cancers are included, the death rate among black men was 22% higher than among white men in 2012-2016, the most recent period discussed in the cancer society’s report. Not every cancer is more lethal for black men. The death rates for leukemia, esophageal, bladder and brain cancers are higher for white men than for black men. But those are relatively rare cancers. The death rates for common cancers such as prostate, lung and colorectal are higher for black men, sometimes much higher. For example, the death rate for prostate cancer is more than twice as high among black men as it is among white men (39.8 per 100,000 population versus 18.1).

At 13%, the difference in the death rate between black and white women is narrower but still sizable. The death rate for some of the most common cancers, including breast and colorectal, is higher among black women than it is among white women.

For men, the incidence patterns, by and large, fit the death rate patterns, with black men more likely to receive cancer diagnoses than white men (22% vs. 9%). But cancer incidence among black women is actually lower by 7% than it is among white women.

Sociopolitical grouping

The reasons for racial disparities in cancer data hinge on how race is defined. Increasingly, investigators are viewing race primarily as a sociopolitical category.

“To categorize people by race is almost like slicing soup — it is impossible,” said Otis Brawley, M.D., in a podcast last year on redefining race. Brawley, now a professor at Johns Hopkins University in Baltimore, was chief medical officer at the American Cancer Society for about 10 years. Brawley says in the podcast that race should be taken into account, but as a sociopolitical grouping, and that cancers may be affected by factors associated with a sociopolitical group such as poverty or living in a more polluted area.

Viewing race as a sociopolitical grouping doesn’t mean there aren’t noteworthy genetic and biologic differences among those groupings. For example, black women are twice as likely to have triple-negative breast cancer (lacking estrogen and progesterone receptors and excess HER2 protein) as white women, and women who have this type of cancer tend to have worse outcomes.

Fixing enrollment

Addressing racial disparity root and branch would mean dealing with racism, housing, employment opportunities, education, nutrition, environmental issues — it’s a daunting list.

A perhaps more manageable problem for organized oncology is the one that Frazier said Merck is working on: improving the representation of African Americansin clinical trials. Samer Al Hadidi, a postdoctoral fellow at Baylor College of Medicine in Houston, and his colleagues reported findings in the Annals of Internal Medicine in June that showed how underrepresented African Americans are in trials. They calculated a participation-to-prevalence ratio of the clinical trials related to 75 FDA-approved cancer drugs. A 1.0 ratio would mean that the number of African Americans in the trials matched the number of African Americans in the patient population. Instead, Al Hadidi found a 0.31 ratio for all cancers combined; for prostate and multiple myeloma, 0.18 and 0.04, respectively.

“For all cancers, the number is extremely low, and it is very low in the cancers that are common among African Americans,”
Al Hadidi says.

Manali Bhave, M.D., a medical oncologist and assistant professor at Emory University School of Medicine in Atlanta, presented findings about black-white differences in investigator-initiated trials of metastatic breast cancer at Emory’s Winship Cancer Institute at ASCO’s annual meeting this year. Some of the results from the small study (62 patients) go against the narrative. Bhave and her colleagues did not, for example, find that African American women were underrepresented (perhaps because of Atlanta’s large black population), nor was there evidence of African American women enrolling after receiving more lines of treatment, which can indicate reluctance to enroll in a clinical trial, lack of referral by doctors or both.

Bhave did spot a trend of shorter survival of African American women in the trials and a greater likelihood that their breast cancer progressed. “I think that, perhaps, suggests there are differences in the disease biology and the response to new drugs that requires some additional investigation,” Bhave says. “There seems to be something about the underlying disease that contributes, at least in part, to poorer outcomes.” She points to an article written by her Emory colleague, Bassel Nazha, M.D., and others that argues that African Americans may not respond to the current crop of cancer immunotherapies because of immune system differences. Nazha’s article was published in the education book of background and think pieces that ASCO puts out in conjunction with each year’s annual meeting.

One of the reasons investigators believe it is important to solve the underrepresentation problem in clinical trials is to discover early on whether African Americans respond differently to a drug.
Al Hadidi also notes that clinical trials are a form of access, and if the experimental drug is safe and effective, it gives participants access to better treatment. For some patients, Al Hadidi says, “if they were not getting those medications, they may not be alive and with us.”

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