Heart transplant patients are four to 30 times as likely to develop skin cancer as healthy people, depending on where they live and other factors, researchers said Thursday. Patients who live nearer the equator and have fairer skin are the most likely to suffer skin cancers and to die from them, the researchers reported in the American Journal of Transplantation.
Transplant patients in general have an above-normal risk of developing cancer because of the need to use immunosuppressive drugs to prevent the transplant from being rejected. Those drugs can also allow a small tumor to flourish, while an unsuppressed immune system might be able to control or eliminate it.
Heart transplant recipients are at a higher risk still because they require the highest doses of such drugs to prevent rejection of the heart. According to the National Institutes of Health, cancers account for about a quarter of all heart transplant deaths in the three years after surgery, primarily skin cancers and cancers of the lymph system, such as non-Hodgkins lymphoma. Why such patients seem particularly susceptible to skin cancer is still unknown.
Several previous studies have attempted to quantify the increased risk of skin cancer, with widely varying results. Many of those studies were conducted in Europe and most involved data from only one or two transplant centers, which limits the general applicability.
Dr. Murad Alam, a dermatologist at Northwestern University in Chicago, and his colleagues studied 6,271 heart transplant patients at 32 U.S. centers who underwent the surgery between 1990 and 2003, using data from the Cardiac Transplant Research Database maintained at the University of Alabama at Birmingham. Those patients represented about a quarter of the 24,758 heart transplants performed in the United States during the period. Among those patients, the team identified 228 cases of basal cell carcinoma (3.6% of patients), 289 cases of squamous cell carcinoma (4.6%), 22 cases of melanoma (0.003%) and six cases of other skin cancers (0.001%).
White patients were much more susceptible to the tumors. After 10 years, only 83% of white patients were free of skin cancer, compared to 99.2% of other patients. Older recipients had 7.6 times the risk of developing skin cancer. Among those 60 over, 74% were skin cancer-free after 10 years, compared to 86% of those under 30. Patients in Southern states had a 20% increased risk of developing skin cancer, while those who had a history of skin cancer before their transplant had double the risk. Two-thirds of those who had a skin cancer before their transplant had developed a new skin cancer by 10 years after their surgery. Heart transplant patients who developed melanoma were six times as likely to die from it as were otherwise healthy people.
The researchers urged heart transplant recipients to use sunblock and to otherwise cover their skin when outside and called on their physicians to monitor them closely for the development of new tumors.