Destructive and topical treatments of skin lesions in organ transplant recipients and relation to skin cancer

Various treatments of keratotic skin lesions and early skin cancers are performed in organ transplant recipients (OTRs) at high risk of skin malignancies but the frequency of their use is unknown. We prospectively assessed the frequency of use of cryotherapy, diathermy, and topical therapies and also investigated their associations with background incidence of histologically-confirmed squamous-cell carcinoma (SCC) and basal cell carcinoma (BCC) in a cohort of OTRs in Queensland, Australia. Median follow-up ranged from 1.7 to 3.2 years across organ transplant groups. Among 285 kidney, 125 lung and 203 liver transplant recipients [382 (62%) male, 380 (62%) immunosuppressed > 5 years, 394 (64%) previously diagnosed with skin cancer], 306 (50%) reported treatment of skin lesions with major types of non-excision therapies during follow-up: 278 (45%) cryotherapy or diathermy; 121 (20%) topical treatments. Of these 306, 150 (49%) developed SCC at double the incidence of those who did not receive these treatments, as assessed by incidence rate ratio (IRR) adjusted for age, sex, type of organ transplant, skin color and history of skin cancer at baseline, calculated by multivariable Poisson regression (IRRadj = 2.1, 95% confidence interval (CI) 1.4–3.1). BCC incidence was not associated with these therapies. Skin lesions in OTRs that are treated with cryotherapy, diathermy, or topical treatment warrant judicious selection and careful follow-up.