LAUSR

Importance There are limited reports on the risks of multiple primary skin cancers in organ transplant recipients (OTRs). Objective To determine the risks over time and risk factors for OTRs developing (1) any skin cancer posttransplant, (2) a subsequent skin cancer after the first posttransplant skin cancer in the data sets used in the study, and (3) 10 or more skin cancers. Design, Setting, and Participants This retrospective cohort study used data from Optum deidentified electronic health record data set (7.7 million patients) and Truven Health MarketScan insurance claims data set (161 million patients) from 2007 to 2017. Skin cancers were identified using diagnosis plus treatment codes for basal cell carcinoma, squamous cell carcinoma, and melanoma; OTRs were identified using 4 or more diagnosis codes for organ transplant. Data analysis took place from January 1, 2007, to December 31, 2017. Main Outcomes and Measures Cumulative risks of (1) any skin cancer treatment posttransplant, (2) a subsequent skin cancer treatment after the first posttransplant skin cancer treatment in our data, and (3) 10 or more skin cancer treatments in OTRs. A Wei-Lin-Weissfeld marginal model was used to evaluate risk factors for any skin cancer. Results A total of 7390 OTRs in Optum and 133 651 in MarketScan were identified, 4.5% and 13.3% of which had had at least 1 skin cancer treatment, respectively. At 2 years after the initial posttransplant skin cancer in the data sets, OTRs had a 44.0% to 57.0% risk of a subsequent skin cancer treatment and a 3.7% to 6.6% risk of having 10 or more skin cancer treatments. Statistically significant risk factors for any skin cancer included age, history of skin cancer, and history of actinic keratosis in both data sets, and male sex and thoracic transplant in MarketScan. Conclusions and Relevance In this retrospective cohort study, approximately half of the OTRs who developed at least 1 posttransplant skin cancer developed a subsequent skin cancer within 2 years, and approximately 1 in 20 developed 10 or more skin cancers. Identifying OTRs at highest risk for multiple primary skin cancers may help target strategies for prevention and early detection.