For decades, clinical research studies underrepresented non-white populations, leaving important knowledge gaps. But medical dermatologist Iris Z. Ahronowitz, MD, and her team used a wealth of data at USC for a first-ever retrospective study involving a majority Hispanic population of solid organ transplant recipients.

Solid organ transplant is among modern medicine's great achievements, each year extending and improving the lives of thousands of people with failing kidneys, lungs, hearts and other organs. But the procedures almost always carry one big problem: the immunosuppressants that prevent the body from rejecting transplanted organs leaves patients at a greater risk for developing various cancers, particularly skin cancers. 

Iris Z. Ahronowitz, MD, Assistant Professor of Clinical Dermatology at Keck School of Medicine of USC

A well-established body of literature has described the dramatically increased risk of skin cancers following solid organ transplant (SOTR), said Iris Z. Ahronowitz, MD, Assistant Professor of Clinical Dermatology at Keck School of Medicine of USC. But in the literature, the majority of patients are Caucasian—leaving question marks about the risk for people with other backgrounds. 

"Nobody had looked at post-transplant skin complications in a primarily Hispanic population, so there wasn't any established knowledge whether Hispanic patients have similar or different post-transplant rates of complications than Caucasians," said Ahronowitz. 

The historical underrepresentation of diverse populations in clinical studies is a common concern that research leaders at USC and across the country have committed to correcting. USC's location in the Los Angeles community, with one of the country's largest Hispanic populations, presented Ahronowitz and her team with just such an opportunity. "We realized we were in an excellent position here at USC to contribute to understanding this population and help address the gap in the research," she said.

Data for non-organ transplant populations has shown that skin cancer rates do vary somewhat between different racial and ethnic groups, explained Ahronowitz, whose research interests include medical dermatology, infectious disease/HIV dermatology, and medical education. "We wanted to see if that difference translated over to solid organ transplants."

USC is also a major transplant center, and thus maintains decades of patient care data. Ahronowitz and her team reviewed the institution's records back as far as 1993 for kidney, lung, liver and heart transplant recipients and found more than 2,000 patients transplanted at USC. More than 50 percent were Hispanic—no surprise given the area's large Hispanic population. 

The researchers did indeed find a difference in skin cancer rates for Hispanic SOTR patients: they had less than half as many skin cancers as non-Hispanic whites, and were less likely than whites to have multiple skin cancers. Other differences included the location of the skin cancers, with a greater tendency to develop skin cancers on the head and neck in the Hispanic patients compared to non-Hispanic whites. 

But another finding was even more striking to the researchers: of the Hispanic SOTR patients included in the study, many had never seen a dermatologist at USC after their transplant. While some may have seen dermatologists outside the USC system, the researchers were dismayed to find that only around 12 percent of the patients had been screened by a dermatologist post-transplant. This has prompted the group to initiate a follow-up study, currently in progress, to better understand factors affecting referral and access to dermatology screening among transplant patients.

"Essentially, this is the first and largest study we’re aware of looking at a majority Hispanic SOTR population," said Ahronowitz. "It demonstrates that Hispanic patients in post-transplant settings have rates of skin cancers that are lower than whites yet still significant, but that substantial numbers may go undiagnosed due to a lack of follow-up screening by dermatologists. It highlights the need to screen these patients regularly and educate them about the risk of skin cancers." 

The study, "Skin cancer and dermatoses in a majority Hispanic population of solid organ transplant recipients," was accepted for publication in the Journal of the American Academy of Dermatology. Along with Ahronowitz, authors are Brandon L. Adler, MD, Jan Smogorzewski, MD, Tiffany Sierro, BS, Orr Shauly, BS, Daria Osipchuk, BS, Melanie Miller, MD, Melissa Mert, MS, Michael W. Fong, MD, Sivagini Ganesh, MD, Hyosun Han, MD, Gino K. In, MD, MPH, Thin Thin Maw, MD, MS, Miroslaw Smogorzewski, MD, PhD, Jenny Hu, MD, Binh Ngo, MD, David Lee, MD. 

The study was supported by a Team Building Grant from the Southern  California Clinical and Translational Science Institute (SC CTSI), which formally brought together a research team that included dermatologists, oncologists, and transplant specialists from nephrology, pulmonology, cardiology and hepatology. 

 "The SC CTSI's team building support gave us the opportunity to sit down together with colleagues across specialties to talk about the challenges we were facing and get everyone on same page about how to address the risk of skin cancer in our post-transplant patients, including topics like education, referrals, and skin checks," said Ahronowitz. "There was tremendous enthusiasm from all the participants to strategize about how to take our care for post-transplant patients to the next level." 

NIH Funding Acknowledgment: Important - All publications resulting from the utilization of SC CTSI resources are required to credit the SC CTSI grant by including the NIH funding acknowledgment and must comply with the NIH Public Access Policy.