BALTIMORE, Aug. 13 (UPI) -- Organ transplant patients are twice as likely as people without transplants to develop melanoma and 3 times as likely to die from it, according to a new study.
Researchers found that patients were more likely to develop melanoma within the first 4 years of taking immunosuppressive drugs meant to keep their bodies from rejecting transplanted organs. Previously, scientists thought the potential for the drugs to influence cancer development would come after many years of taking the drugs.
"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, a PhD student at the Johns Hopkins Bloomberg School of Public Health, in a press release. "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."
Researchers started by analyzing the 139,991 non-Hispanic white transplant patients tracked as part of the Transplant Cancer Match Study, which is linked to the Scientific Registry of Transplant Recipients, identifying 519 patients with melanoma.
After reviewing the 519 melanoma patients' records, the researchers compared 182 patients' treatment outcomes against another data set of 130,000 people with melanoma. Over the course of 15 years, they found that 27 percent of transplant patients died of the melanoma while 12 percent of non-transplant melanoma patients died of the disease.
Of the melanoma cases studied, the researchers reported that late-stage cases of melanoma tended to be associated with drug treatments started immediately after a patient's transplant to prevent their bodies from attacking new organs. In early stage melanoma, they found those patients to be longer term transplant patients who received the drug azathioprine, which multiplies the effects of ultraviolet radiation and may be responsible for the cancer's development.
Robbins said that closer screening of transplant patients before surgery for melanoma was necessary so that it could be factored into post-transplant treatments, and that much closer monitoring after transplants was necessary. Missing either, she said, could be the reason that late-stage melanoma is discovered so late in these patients.
The study is published in the Journal of Investigative Dermatology.