Cancer Disparities Heighten Need to Recruit Hispanics for Clinical Trials

Anand B. Karnad, MD

Chief, Division of Hematology Oncology

Professor, Castella Foundation Endowed Chair in Aging

Chair, Protocol Review Committee for the Cancer Center Support Grant

University of Texas Health Science Center

Cancer Therapy & Research Center

The Hispanic population in the United States represents the fastest-growing segment of the population (expected to reach 30% of the nation’s total by 2050), and faces significant cancer health disparities: lower cancer awareness and lower screening rates leading to a higher incidence of certain cancers and higher mortality rates from at least six cancers compared with non-Hispanic whites.^1,2

Yet Hispanics are dramatically underrepresented in clinical trials and findings often are not reported with participants’ ethnicity in mind.

Only 2.2% of patients enrolled in clinical trials during a 10-year period were Hispanic, according to one study.³ An analysis conducted at the University of Texas Health Science Center Cancer Therapy & Research Center (CTCR) found that only about 8% of a sampling of potentially practice-changing clinical trials provided information on the accrual of Hispanics.⁴ For those trials that did report ethnicity, just 3.9% of participants were Hispanic.

There are strategies that have proved successful at CTCR for boosting enrollment of Hispanics in clinical trials, and these approaches can help broaden clinical trial recruitment so that this significant segment of the nation’s population is included in the development of life-saving therapies.

Disparity in Cancer Rates

It is important to note that the Hispanic population is heterogeneous; it is made up of different immigration patterns and genetic ancestry, and has been exposed to a variety of lifestyle practices and environmental factors.

Therefore, it is not surprising that within the Hispanic population, incidence patterns of different cancers can vary up to 5-fold based on country of origin. The Hispanic population also faces obesity-related health disparities and other inequalities—leading to a dire need for cancer health disparity research in this population.

Cancers that are disproportionately common in the Hispanic population include:^1,2

• double the incidence in Hispanics compared with non-Hispanic whites, with a higher mortality rate
• 2 to 2.5 times more common in Hispanic women
• 4 to 5 times higher among Hispanics from South or Central America
• substantially higher among Puerto Rican immigrants and in Hispanic populations as a group
• a higher incidence of leukemia, retinoblastoma, osteosarcoma, and germ cell tumors.

Genetic factors (ancestry informative markers), environmental factors (physical activity, obesity, diet, tobacco, and alcohol), and cultural factors (machismo and fatalism), may explain some of the cancer health disparity, but there is paucity of data for causality in many common cancers including for some of the devastating epidemics of cancer in this population (eg, liver cancer).

Hispanics have the highest incidence of lack of health insurance compared with any other ethnic group and this socioeconomic factor drives a significant burden of their health disparity.

Need for Clinical Trial Enrollment

Cancer clinical trials, the invaluable research engine that drives the translation of new knowledge from discovery in the laboratory to the bedside of the patient and ultimately to practice-changing interventions that save lives, are now dramatically altering the landscape and natural history of cancer. There are several hundred new agents for the treatment of cancer that are in various phases of testing and thousands of cancer clinical trials are being conducted all over the world.

Participation in clinical trials by minority populations is essential if we are to overcome cancer health disparity and reduce the burden of cancer in these populations. Although there has been a national agenda for Latino cancer prevention and control published in 2005, and up-to-date statistics on Hispanic cancers in the United States published in 2012, there has not been a concerted effort to focus on Hispanic participation in and accrual to cancer clinical trials.

CTCR researchers have shown that there is little evidence of Hispanic accrual on clinical trials published in high-impact peer-reviewed journals, and have called attention to the need to focus on enhancing Hispanic accrual on to cancer clinical trials.4

We searched five journals for studies that likely would change the standard of care and then examined the findings for data on accrual of Hispanics. Only 33 of 159 clinical trials (~20.75%) offered data about the accrual of minorities. Of these, only 13 studies (8.18%) included information on participation by Hispanics. Accrual ranged from one patient (0.5%) enrolled in a lung cancer trial to 17 patients (26%) participating in an acute lymphoblastic leukemia study.

Overcoming Barriers

Patient-related barriers to clinical trial participation may include a lack of awareness, challenges with language barriers, and the burden of travel and costs of care.

There are also physician-related barriers. Latino physicians are less involved with clinical trials than white physicians, and report feeling that clinical trials have less value. The burden of the clinical trial process itself—diverting time away from practice—discourages physicians from encouraging participation in or recommending clinical trials to their patients.

At CTRC, where the majority of the estimated 4.49 million people who live within our catchment area are Hispanics, we have been successful in recruiting large numbers of Hispanics for clinical trials. In 2012, 45% of the 822 patients enrolled in clinical trials conducted at CTCR were Hispanic.4

We have achieved this level of participation through a multifaceted program that includes offering consent forms in Spanish and bilingual study team members to counsel patients, making minority recruitment a specific goal in the clinical trial protocol, and creating a toolkit to help investigators spread word of the trial to the target patient population.

Throughout the oncology community, the top professional education goal should be to train more Spanish-speaking providers and staff. Educating the providers and the public about the importance and value of participating in cancer clinical trials remains a high priority.

It is imperative that we develop affordable, culturally sensitive, linguistically appropriate, and timely access to cancer clinical trials—and, to paraphrase a National Cancer Institute message about the importance of clinical trials: Hispanic Lives Depend Upon It.

References

1. Haile RW, John EM, Levine, AJ. A review of cancer in U.S. Hispanic populations. Cancer Prev Res. 2012;5(2):150-163.
2. American Cancer Society. Cancer Facts & Figures for Hispanics/Latinos 2012-2014. Published 2012. http://www.cancer.org/acs/groups/content/@epidemiologysurveilance/documents/document/acspc-034778.pdf. Accessed August 27, 2014.
3. Kwiatkowski K, Coe K, Bailar JC, Swanson GM. Inclusion of minorities and women in cancer clinical trials, a decade later: have we improved [published online May 14, 2013]? Cancer. 2013;119(16):2956-2963.
4. Parra A, Karnad AB, Thompson IM. Hispanic accrual on randomized cancer clinical trials: a call to arms. J Clin Oncol. 2014;32(18):1871-1873.