People who receive a kidney transplant are nearly four times more likely than the general population to develop melanoma, a rare but deadly form of skin cancer, according to a study led by Christopher Hollenbeak, Ph.D., associate professor, Departments of Surgery and Health Evaluation Sciences, Penn State College of Medicine, Penn State Milton S. Hershey Medical Center.
The study, to be published in CANCER, a peer-reviewed journal of the American Cancer Society (Nov.1, 2005 issue), indicates increased risk for patients who undergo kidney transplantation and who receive long-term immuno-suppression. Furthermore, risk was highest overall in men -increasing with age- but significantly lower in women and African-Americans.
"The take-home message is that kidney transplant patients-especially men-should have a regular, complete skin examination as part of their routine health care," says Hollenbeak. "In addition, kidney transplant recipients should be educated about melanoma and instructed on the importance of routine self-examination."
In the largest study to date, Hollenbeak and his colleagues compared melanoma incidence rates from a registry of renal transplant patients (89,786 patients) to melanoma incidence rates from general population data.
Of the various types of skin cancer, melanoma is one of the deadliest, with a mortality rate up to 6 percent in some regions of the world. The classic risk factors for melanoma are ultraviolet radiation, commonly caused by sunburns, a suppressed immune system, and family history of abnormal moles. Studies demonstrate that the immune system plays a critical role in monitoring the body for-and destroying-early cancerous cells, including melanoma.
Prior studies have shown that patients taking immunosuppressants after organ transplantation to be at higher risk for all cancers, but disagree that there is a link to higher risk of skin cancer. The baseline low incidence of melanoma in the general population may contribute to conflicting data. Low incidence of disease means that more people need to be studied to discern a true link between immunosupressants and a greater risk for melanoma.
They found that renal transplant recipients are 3.6 times more likely to develop melanoma than the general population. Though some melanomas will develop immediately after transplant, risk continues to increase approximately 5 percent per year from date of transplant. Men who have had a kidney transplant are at greatest risk for melanoma, and risk of melanoma increases rapidly with age. In contrast, while female kidney transplant recipients are also at increased risk, their risk is significantly lower than men and does not increase with age.
"Kidney transplant patients, who are receiving long-term immunosuppression," conclude Hollenbeak and his colleagues, "have a 3.6-fold increase in the incidence of melanoma when compared to the general population," and should receive regular complete skin examinations.