"If you are living with a kidney transplant, you should be aware of the risk of cancer, particularly melanoma," said study author Christopher S. Hollenbeak, an assistant professor of surgery and health evaluation sciences at Penn State College of Medicine.
The findings appear in the Nov. 1 issue of Cancer.
Hollenbeak conducted the study because previous studies looking at the risk of melanoma among kidney transplant patients had produced conflicting results. One study, for instance, followed more than 5,000 patients for more than 24 years and found no increased risk. But another one looked at more than 2,500 kidney and heart transplant recipients over 30 years and found a 3.4-fold increased risk, he said.
Hollenbeak's team examined nearly 90,000 patients who underwent kidney transplants between 1988 and 1998, using the U.S. Renal Data System. Of these, 246 people got melanoma. This risk was 3.6 times greater than the general population.
The risk of melanoma risk was greatest in men and increased with age, the researchers found. And while women were at increased risk, too, their risk was markedly lower than men's and did not increase with age. Blacks were seven times less likely to develop melanoma than other races, the scientists said.
Did the finding surprise Hollenbeak? "Yes, it did," he said. "That's a pretty big increase in risk."
Kidney-transplant patients receive long-term immunosuppressant drugs, and it is known that immunosuppression is associated with melanoma risk. Other risk factors for melanoma include atypical moles, a history of blistering sunburns, and a personal or family history of malignant melanoma.
An estimated 59,580 persons in the United States will find out they have melanoma this year, according to the American Cancer Society, and nearly 8,000 will die of the disease this year.
Kidney transplant patients face a higher risk of other types of skin cancers as well, the study authors said.
"Melanoma is much more rare than some other types of cancer," Hollenbeak said, "but much more devastating." It only accounts for about 4 percent of all skin cancer cases but causes the most skin cancer deaths, according to the cancer society. Non-melanoma skin cancers are usually highly curable.
A retired transplant surgeon praised the study.
"This is really an extremely well-done study, and an important study," said Dr. Myron Kauffman, a medical consultant for United Network for Organ Sharing.
"The majority of them [kidney transplant patients] are on immunosuppressants for life," Kauffman said. But over time, the dosage is usually decreased, he added.
The take-home point for kidney transplant patients, said Hollenbeak, is awareness. "It's important to learn from your doctor how to do a self exam to check for these things." Kidney transplant patients should also have regular visits to a dermatologist, he added.
More information
To learn more about melanoma, visit the American Cancer Society.
