A large study showing an increased risk of keratinocyte carcinoma (KC) in children who receive a solid-organ transplant highlights the need for early education about risk reduction and more research to determine optimal timing for screening, say an investigator and two dermatologists with expertise in transplant-related skin issues.
The increased incidence of KC in pediatric transplant recipients is “really high, so we definitely know there’s risk there,” just as there is for adult recipients of solid-organ transplants, said Cathryn Sibbald, MD, MSc, a dermatologist at the Hospital for Sick Children in Toronto and coauthor of a research letter published in June in JAMA Dermatology.
Dr. Cathryn Sibbald
For their study, Dr. Sibbald and her coinvestigators turned to the Ontario Health Insurance plan database, which covers health care for Canadian citizens and qualified residents in the province. They identified 951 patients younger than the age of 18 who received a solid-organ transplant between 1991 and 2004 at an Ontario hospital
They then used a validated health insurance claims–based algorithm to identify diagnoses of KC for the transplant recipients and for more than 5 million age-matched controls. KC, including squamous and basal cell carcinoma, is the most prevalent skin cancer for people who have had a solid-organ transplant.
Fifteen posttransplant KCs (10 patients, 1.1%) were reported a mean of 13.1 years after transplant, with none reported in the first 4 years. The mean age at transplant was 7.8 years, and the mean age at KC diagnosis was 25.2 years. Kidney transplants were the most common (42.1% of transplantations). Most of the transplants recipients (eight patients) who developed KC had kidney transplantation, and most of them had functional graft at the time of KC diagnosis.
Researchers found an increased incidence of KC compared with that of the general population (standardized incidence ratio, 9.09; 95% confidence interval, 5.48-15.08). And the risk for KC increased with time since transplant, with adjusted hazard ratios for KC of 3.63 (95% CI, 0.51-25.77) for 1-5 years, 5.14 (95% CI, 1.28-20.55) for 5-10 years, and 4.80 (95% CI, 2.29-10.08) for 10 years or more, compared with the control population.
Several years ago, another research team performed a similar population-based cohort study of adult transplant recipients in Ontario and found a 6.6-times increased risk of KC in transplant recipients compared with the general population.
Sun protection and skin cancer screening
In commenting on the study, Sarah Arron, MD, PhD, a San Francisco Bay area dermatologist and immediate past president of the International Immunosuppression and Transplant Skin Cancer Collaborative (www.itscc.org), said she feels “reassured” that young transplant patients tend not to develop the skin cancer until young adulthood.
Dr. Sarah Arron
A ”large study like this is important because the overall rate of KC is low in this age group,” she noted.
The findings “suggest that we can focus our efforts on prevention during childhood, with sun protection and skin cancer education,” she said. “Then, as these children move into adulthood, we can begin screening with skin examinations. Of course, [any child] with a skin lesion or mole that concerns their parents or transplant team should be referred to dermatology for evaluation.”
Pediatric transplant recipients and their parents are most interested in learning about skin cancer prevention either before or immediately after transplantation, according to a survey by other researchers.