A recent study published in the Journal of Investigative Dermatology has determined that people who receive organ transplants are three times more likely to die from melanoma. Healthcare professionals have long known that transplant recipients were more likely to develop melanoma — the most aggressive type of skin cancer — than the general population.

This study suggests that immunosuppressive medications make organ recipients more likely to develop late-stage skin cancers for which treatment isn't as effective. In fact, the study shows organ recipients are four times more likely be diagnosed with regional-stage melanoma, meaning the cancer has spread to other areas of the body.

"We knew that melanoma was more likely in transplant recipients, but we thought it might be a function of intensive screening since they are very likely to develop less deadly forms of skin cancer and are checked regularly by dermatologists," said Hilary A. Robbins, MSPH, a Ph.D. student in the Department of Epidemiology at the Johns Hopkins Bloomberg School of Public Health in Baltimore. Robbins is the study's first author and conducted much of the research while at the National Cancer Institute.

"To the contrary, we were surprised to see that transplant recipients were particularly at risk for developing melanomas that weren't found until they had already spread."

Previously, it was believed that the risk of aggressive melanoma resulted from years of cumulative immunosuppressive drug therapy. However, Robbins and the research team determined the risk of melanoma was much higher in the four years immediately following the transplant.

To conduct the study, the team looked at nearly 140,000 transplant recipients in the Transplant Cancer Match Study. The study links the Scientific Registry of Transplant Recipients, which includes data on about half the transplant recipients in the United States between 1987 and 2010. Among the group, 519 melanomas were discovered.

With a separate set of data, the researchers compared the outcomes of 182 transplant patients with melanoma with the outcomes of more than 130,000 other people with melanoma. Over a 15-year period, 27 percent of the transplant recipients died from melanoma. Only 12 percent of nontransplant patients died as a result of melanoma.

Ultimately, the researchers determined that patients who had melanoma and a had been a transplant recipient were three times more likely to die from melanoma. Even transplant patients who were diagnosed early or had a small melanoma were three times more likely to die than nontransplant patients.

The study identified possible causes for the prevalence of melanoma among organ recipients. Late-stage melanoma among transplant patients may be triggered by medication given near the time of the transplant. The drug stops T-cells from functioning and prevents the body from rejecting the new organ. Early-stage melanoma was more likely among recipients who received azathioprine, a maintenance drug that exacerbates the effects of ultraviolet radiation.

Robbins said transplant recipients should be carefully screened for melanoma before receiving an organ since it's possible that a melanoma could be present and immunosuppressive drugs allowed it to spread quickly. Closer monitoring after transplant might also allow for earlier detection, she said.