Malignancies After Renal Transplantation: Frequency, Etiology, and Prognosis-A Single Center Experience.

: Renal transplant recipients face significant long-term graft and patient loss due to post-transplant malignancies. This study aimed to characterize post-transplant malignancies, determine mortality risk factors, and evaluate patient outcomes. : This retrospective study included 2052 kidney transplant recipients who underwent transplantation between 1976 and 2019 at our institution, other national centers, or international facilities, and who had at least six months of follow-up. Regardless of the transplant center, all patients were followed exclusively at our nephrology department for post-transplant care. A comprehensive review of patient files was conducted, encompassing demographic data, malignancy type and treatment, mortality rates, tissue compatibility assessments, viral serology results, immunosuppression protocols, acute rejection history, and pre-transplant malignancies. The relationships between these variables and mortality were examined. : A total of 167 malignant events were observed in 163 patients out of 2052 renal transplant patients (7.9%). The female patients comprised 34.4% ( = 56) of the participants. Ages at transplantation and malignancy diagnosis had medians of 40.0 (13-72) and 50.0 (23-78) years, respectively. The leading malignancy was skin cancer at 30.0%, with Kaposi sarcoma at 11.3% and post-transplant lymphoproliferative disease at 10.6% following. Of the patients followed up, 58.9% (93 patients) had mortality. In univariate analysis, older age at transplant, older age at malignancy diagnosis, and male sex were associated with mortality; however, no independent predictors were identified in the multivariate model (all > 0.05), likely due to sample size limitations and inter-variable collinearity. Mortality showed statistically significant associations ( < 0.05) with increased age at transplantation, increased age at malignancy diagnosis, and male gender. : Post-transplant malignancies significantly compromise both graft longevity and patient survival. Particularly aggressive skin cancers demand heightened clinical vigilance. Early detection through regular dermatological screening, patient education, and timely biopsies must become integral to long-term transplant care protocols.