The Link Between Heart Transplants and Increased Melanoma Risk

We have long known that organ transplant recipients have a significantly increased risk of many types of skin cancer, and according to a recent analysis, this risk extends specifically to melanoma. Data pooled from multiple independent studies shows heart transplant recipients have an increased risk of melanoma.

It was previously known that kidney transplant recipients are at risk for melanoma, and the risk was suspected to be similar for heart transplant recipients. The new study confirms this association.

An Internal Medicine group at the Lakeland Regional Health Medical Center in Lakeland, Florida, led the research analysis. However, the study’s heart transplant patients (n=22,415) resided in Australia, Canada, the Czech Republic, Denmark, Finland, France, Sweden, and Taiwan, but mainly in the U.S. (n=16,325).

Overall, 579 cases of melanoma occurred in the patient population studied. The numbers showed an elevation when compared to the general U.S. population, which has a rate of approximately 21 cases of melanoma per 100,000 adults. Extrapolating a population of 22,415 (the number included in the study), the equivalent number of expected melanoma cases would equal approximately 4 or 5 people, so the increase is roughly four times greater.

Immune-suppressing drugs are required for organ transplant recipients to prevent the rejection of a new organ. Although donors and recipients must match blood type and other cell-surface protein markers, the system is so complex that the human body still recognizes the new organ as having foreign parts. Without suppressing the immune system, the new organ would be under constant attack and eventually rejected.

Transplant recipients receive high doses of immune-suppressing drugs for a long period, which can be the rest of their lives. Medications used by patients in the study included azathioprine, corticosteroids, cyclosporine, mycophenolate mofetil, prednisolone, sirolimus/everolimus, and tacrolimus.

Unfortunately, the immune system constantly interacts with the skin to prevent cancer, which is how suppressing this critical process presents risk. It is a contributing reason why organ transplant recipients’ life expectancy is less than the general population.

Organ donors are carefully screened for cancer and other transmissible infections that would make them ineligible to donate organs. However, even the healthiest organs are detected as foreign in another human body.

The results are concerning because the number of heart transplants in the U.S. continues to rise. Although this lifesaving procedure is essential, it is also important for clinicians to understand the associated cancer risks to manage post-transplant patients properly.

This summary is based on the article “International incidence of melanoma in heart transplant recipients: a meta-analysis” by Paola Campillo, Alice Kesler, Camila A Ramírez, et al. published in Melanoma Research on October 7, 2024. It was published online ahead of print.