Non-Melanoma Skin Cancer in Transplant Recipients: A Single-Centre Retrospective Cohort Study on the Role of Transplant Type, Immunosuppressive Exposure, and Tumor Subtypes

Background: Non-melanoma skin cancer (NMSC) is a frequent long-term complication in transplant recipients, mainly due to chronic immunosuppression. Its incidence varies by transplant type and regimen, but existing evidence is often fragmented. Objective: To assess long-term incidence and risk factors for NMSC, comparing transplant types, immunosuppressive regimens, and tumor subtypes. Methods: This retrospective cohort comprised 901 transplant recipients (1975–2024) who were under long-term dermatologic follow-up. Data on transplant type, immunosuppressive regimen/duration, and tumor subtype were analyzed. NMSC-free survival was evaluated with Kaplan–Meier curves; Cox regression assessed predictors. Results: Among 901 transplant recipients, 191 (21.2%) developed at least one NMSC during long-term follow-up. Crude incidence rates ranged between 1.88 and 2.68 per 100 person-years across immunosuppressive drug classes and agents. In multivariable Cox models, older age at first transplant was independently associated with higher NMSC risk (HR 1.07 per year, 95% CI 1.06–1.09, p < 0.001). Sex, transplant group, and ever-use of individual immunosuppressive agents were not significantly associated with NMSC risk after adjustment. Conclusion: In this long-term cohort, NMSC risk increased with age at first transplant, whereas transplant organ and ever-use of major immunosuppressive agents were not independently associated in adjusted models. Over an extended follow-up, NMSC accumulated steadily, with crude incidence rates around 1.88–2.68 cases per 100 person-years across immunosuppressive classes and agents, underscoring the cumulative nature of skin cancer risk under chronic immunosuppression. Our results reinforce the need for sustained, long-term dermatologic surveillance, particularly in older patients undergoing transplantation.