Higher Skin Cancer Risk Among Recipients of Lung and Heart Transplants

Recipients of well-matched heart and lung transplants may have a higher risk for skin cancer posttransplant than patients who undergo other solid-organ transplants, explain Yi Gao, MD, Department of Medicine, Banner University Medical Center, Phoenix, Arizona, and colleagues in their recent study (JAMA Dermatol. 2019 Jan 23. Epub ahead of print).

“Risk factors for the development of skin cancer after solid-organ transplant can inform clinical care, but data on these risk factors are limited,” they said. Dr Gao and colleagues sought to evaluate the relationship between HLA antigen mismatch and the occurrence of skin cancer after a solid organ transplant.

Using data from the Scientific Registry of Transplant Recipients, the investigators conducted the retrospective Transplant Skin Cancer Network study of 10,649 adults who underwent primary solid-organ transplantations between January 1, 2003, and December 31, 2003, or between January 1, 2008, and December 31, 2008. The primary end point of the study was time until skin cancer diagnosis posttransplant, including squamous cell carcinoma, melanoma, and Merkel cell carcinoma.

A medical record review was done to match patients with skin cancer outcomes, and the secondary analysis of these data were conducted between August 1, 2016, to July 31, 2017. Dr Gao and colleagues used the 2016 Organ Procurement and Transplantation Network guidelines to calculate HLA antigen mismatch, and a multivariate Cox proportional hazards regression model to examine the risk for skin cancer.

Of the 10,649 organ transplant recipients included in the study, 6776 (63.6%) were men; the mean age of the patients was 51 years. Overall, the recipients all contributed to 59,923 years of follow-up.

For every additional mismatched allele, there was a 7% to 8% drop in the risk for skin cancer (adjusted hazard ratio [HR], 0.93; 95% confidence interval [CI], 0.87-0.99; P = .01). According to a subgroup analysis, the protective effect of HLA antigen mismatch was statistically significant in patients who underwent lung (adjusted HR, 0.70; 95%CI, 0.56-0.87; P = .001) and heart (adjusted HR, 0.75; 95%CI, 0.60-0.93; P = .008) transplantations, but not in those who received liver, kidney, or pancreas transplants.

Of note, the degree of HLA-DR mismatch was most statistically significant for skin cancer risk, but the same could not be determined for HLA-A or HLA-B mismatch (adjusted HR, 0.85; 95%CI, 0.74-0.97; P = .01).

“The HLA antigen mismatch appears to be associated with reductions in the risk of skin cancer after solid-organ transplant among heart and lung transplant recipients,” Dr Gao and colleagues concluded.

“[T]his finding suggests that HLA antigen mismatch activates the tumor surveillance mechanisms that protect against skin cancer in transplant recipients and that skin cancer risk may be higher in patients who received a well-matched organ,” they said.—Hina Khaliq