Organ transplant recipients are twice as likely to develop melanoma as people who do not undergo a transplant, and three times more likely to die of the dangerous skin cancer, a new research has warned.
The research led by a Johns Hopkins Bloomberg School of Public Health student suggests that the immunosuppressive medications that transplant recipients receive to keep them from rejecting their new organs - especially the high doses administered at the time of transplant - may make them more susceptible to later stage cancers that are harder to cure.
Researchers found that transplant recipients were four times more likely to be diagnosed with regional stage melanoma, which has begun to spread to other parts of 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, a PhD student in the Department of Epidemiology at the Bloomberg School.
"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," said Robbins, who conducted much of the research while working at the National Cancer Institute.
The researchers also found that the risk of aggressive melanomas was especially increased within the first four years after transplant.
For their research, Robbins and the team studied 139,991 non-Hispanic white transplant recipients in the Transplant Cancer Match Study, which is led by Eric A Engels, a senior investigator at the National Cancer Institute.
The study links the Scientific Registry of Transplant Recipients, which captures data on all transplants in the US, with 15 population-based cancer registries, and includes information on almost half of the country's transplant population between 1987 and 2010.
The researchers found 519 melanomas in this group and analysed risk factors for developing melanoma.
Using a different data set, the researchers compared outcomes among 182 melanoma patients in the transplant group with more than 130,000 other people with melanoma. Over 15 years, 27 per cent of the transplant recipients died of their melanoma, as compared to 12 per cent of the non-recipients.
The researchers found that melanoma patients who had received a transplant were three times more likely to die from their melanoma, even for melanomas that were diagnosed at an early stage or were very small.
The researchers found that the late-stage cases of melanoma were associated with use of medication given at the time of transplant that essentially stops T-cells - the main cells of immune response - from functioning in order to keep them from attacking the new organ.
Meanwhile, early-stage melanomas were more likely to be found in recipients who were administered a medication called azathioprine, a maintenance drug given long term to some transplant recipients.
