City of Hope scientists are studying how diverse populations have different risk factors for and are affected differently by prostate, lung, skin, breast, colon and other cancers, as well as other diseases.
Different races and ethnicities have different physical, environmental and genetic factors and vulnerabilities that come into play in disease processes. That is why diversity in clinical trials is so critically important. For example, a medication may affect Black and white patients differently. If there is little to no Black representation during the clinical trials for that drug, this crucial information will be missed, and patients may be treated with a medication that either causes harm or has no beneficial effect.
Rick Kittles, Ph.D.
“It’s not OK that in the U.S., African Americans have had the highest overall cancer death rate for more than four decades,” says Rick Kittles, Ph.D., associate director for health equities and professor and director of the Division of Health Equities at City of Hope.
The situation is rife for change, which can happen when scientists recognize the problem and work together to address it. “It’s incredible what can happen when you put the minds of physicians, clinical trialists and scientists together who are concerned about eliminating health disparities and improving treatment options for men [with prostate cancer] who are currently incurable,” says City of Hope’s Leanne Burnham, Ph.D.
Here are just a few recent studies by City of Hope researchers that illustrate why diversity in clinical trials is so important.
Why Diversity in Clinical Trials is Critical
One of the most effective treatments for substance abuse is a drug called naltrexone — effective, that is, if you’re white.
If you’re African American, it probably won’t work at all.
It’s a prime example of what happens when clinical trials lack racial diversity, the subject of an essay published Jan. 15 in Cell Press co-authored by Kittles and Burnham.
The paper presents a powerful case for diversity in clinical trials — especially given the importance of genetics in creating a new generation of precision drugs.
“Genetic variation isn’t random, it’s structured according to population history, and that’s why genetic ancestry is so important,” Kittles said. “If you focus on just one population, you’re going to miss a lot of data — and most research has been driven by white men.”
Targeting Multiple Myeloma in Blacks
Thanks to a $4 million, multiyear R01 grant from the National Cancer Institute, new research will study the efficacy of the arthritis drug leflunomide in preventing or delaying the evolution of high-risk smoldering multiple myeloma (SMM) to overt multiple myeloma, a cancer that presents significantly more often in the Black population.
Steven Rosen, M.D.
SMM is an early precursor to multiple myeloma, which is twice as common in African Americans and has double the mortality rate among this population.
“Despite the strides in the treatment of multiple myeloma in recent years, African Americans have experienced much smaller and less significant improvements in outcomes,” explained Provost and Chief Scientific Officer Steven Rosen, M.D., the Irell & Manella Cancer Center Director’s Distinguished Chair, who is a co-principal investigator for the study. “We’re comparing results in Black versus Caucasian populations and studying the use of leflunomide and its potential anti-myeloma activity.”
Skin Color Linked to Vitamin D Deficiency
One day, physicians may be able to look at an African American’s skin color and, with the help of other determinants, know if prescribing vitamin D supplements would lower that person’s risk of getting cancers of the prostate, colon, rectum or breast.
“We should not shy from this new study looking at the genetics of skin color and its effects on vitamin D deficiency, because being ‘colorblind’ is what has led to the widespread health disparities that we as a society are now trying to address,” Kittles said of the City of Hope-led study.
“Skin color has strong social and biological significance — social because of race and racism, and biological because over 70% of African Americans are vitamin D deficient, resulting in increased risk for cancer and cardiovascular disease,” Kittles added. Notably, the difference in cancer death rates between African Americans and whites is 14%.
Kittles and his colleagues are exploring how they can one day leverage their newly identified risk score in doctors’ offices — potentially creating a precision medicine tool. For example, depending on skin tone, occupation and lifestyle, doctors can better prescribe the correct dose of vitamin D supplementation.
“This study is an example of the interplay of race and skin color on health, and how if we ignore things such as the color of a person’s skin, we may be ignoring potential medical issues, thus contributing to health care disparities,” Kittles said.
“This study is an example of the interplay of race and skin color on health, and how if we ignore things such as the color of a person’s skin, we may be ignoring potential medical issues, thus contributing to health care disparities,” Kittles said.
Multiracial Prostate Cancer Study
For Burnham, the search for a more effective prostate cancer treatment is deeply personal. As an African American, she’s experienced the toll this disease has taken on her family and her community.
The facts are that African American men are the most likely to be diagnosed with advanced and incurable prostate cancer and, according to a cancer disparities report from the American Association for Cancer Research, they have a 111% higher risk of dying from it.
Leanne Burnham, Ph.D.
“If you detect prostate cancer early enough it is nearly 100% curable,” said Burnham. “The problem is that a lot of men have no symptoms, and the cancer has spread before many Black men have been tested.”
This is partly because African American men tend to get prostate cancer at an earlier age than other races, so while it’s generally recommended that men discuss screening with their physicians beginning at age 55, African Americans need to begin at 45, or even 40 if they have extensive family history.
Another problem is that the effectiveness of a treatment is often related to genetic factors — yet the patients enrolled in most clinical trials are primarily white.
“It’s not a secret that clinical trials typically do not enroll enough non-white participants,” she said. “So we are strategically accruing African American men to studies to advance precision medicine by exploring potential racial/ethnic differences in drug efficacy and outcomes due to genomic variation.”
Colorectal Cancer Deadlier for Blacks
Colorectal cancer is more prevalent among Black people, a group that has the highest rates of death for an illness that is curable if caught early.
“The unfortunate reality is that minorities, especially Black people, have a much lower chance of getting lifesaving cancer treatment. Health care works within a social construct, and to change health disparities, we need social change,” said Mustafa Raoof, M.D., M.S., surgical oncologist at City of Hope and senior author of a study published in JAMA Network Open last September.
Mustafa Raoof, M.D., M.S.
City of Hope researchers retrospectively looked at the data of 16,382 adult patients in the California Cancer Registry and found that Black patients were the least likely to receive chemotherapy (59% compared to 65% among white people) and had a 17% higher chance of death compared to white people, even when the scientists controlled for age, sex and comorbidities.
“These troubling statistics are the result of a disparity in access to health care,” Raoof said. “We observed that if Black people with metastatic colorectal cancer had access to subspecialists with expertise in liver resection, they would not experience higher numbers of unnecessary deaths due to underutilization of lifesaving therapies."
Harsh Truths and a Call to Action
On Sept. 16, the American Association for Cancer Research (AACR) released its inaugural Cancer Disparities Progress Report — and they pulled no punches. In it, they describe the devastating gap in cancer treatment and outcomes based on race, ethnicity, socioeconomic status, sexual orientation and more.
On the steering committee for this groundbreaking report was City of Hope’s Kittles, an expert in genomic research.
Of major concern is the group most affected by these inequalities, the African American community. The report details the disparities for African Americans as well as many other groups, highlights areas where some progress has been made, and lays out the paths toward significant solutions.
These selected statistics provide some enlightening examples of what the report found — and the discrepancies are dramatic.
- African American men have a 111% higher risk of dying from prostate cancer than whites.
- African American women are 39% more likely to die from breast cancer compared to whites.
- Asian/Pacific Islander adults are twice as likely to die of stomach cancer than whites.
- Native Americans and native Alaskans are twice as likely to develop liver and bile duct cancer.
Some progress toward closing this health gap has been made. In 1990, the cancer death rate for African Americans was 33% higher than the death rate for whites. In 2016, it was 16% higher. An improvement, yes — but still a huge discrepancy.
The AACR laid out a powerful vision in their report, and their description of what they hope to achieve is worth quoting:
“By making sure that cancer health disparities research is a national priority, Congress can help us transform cancer care for all people, regardless of their race, ethnicity, age, gender, sexual orientation, socioeconomic status or the communities in which they live. When this support is coupled with increased collaboration among all stakeholders, achieving the bold vision of health equity will become a reality.”
AccessHopeTM, a wholly owned subsidiary of City of Hope, is working to reduce cancer health disparities in underserved populations. Read more.