Post-renal transplant malignancies; etiology, frequency and prognosis

Introduction and Aim: Post-transplant malignancies are a significant cause of graft and patient loss in the long term post transplantation. The aim of this study was to establish post-transplant malignacy's type, incidence, risk factors affecting mortality and analyzing the prognosis of kidney transplantation patients followed by the Transplantation Clinic of Istanbul Faculty of Medicine. Material and Method: Between January 1976 and June 2019, a total of 2052 patients underwent renal transplantation at the centers of Istanbul Faculty of Medicine, other transplantation centers in country, or transplantation centers abroad, and were followed for more than 6 months by the Istanbul Faculty of Medicine Transplantation Clinic were included in this study. The patients files were retrospectively screened for demographic features, types of the malignancy, treatments of malignancy, incidence of mortality, tissue compatibility, viral serology, induction and maintenance immunosuppression regimens, history of acute rejection and pretransplant malignancies were determined and the relationship between these variables and mortality was analyzed. Results: Malignancy was found in 158 patients (7.69%) as 167 (8.1%) malignancy events in 2052 patients. In this study, 102 (64.5%) patients were male and 56 (35.5%) were female. The mean age at the time of transplantation was 40.9 ± 11.9 years. The mean follow-up period was 172.9 ± 92.4 months and the mean age at the time of malignancy was 58.6 ± 11.6 years. The most common malignancy was skin malignancy in 48 (30.0%) patients. This was followed by Kaposi's sarcoma in 18 (11.3%) patients and post-transplant lymphoproliferative disease in 17 (10.6%) patients. Non-skin solid organ malignancies were detected in 52 (32.5%) patients. Among these, 11 thyroid papillary carcinomas, 8 colon adenocarcinomas and 8 breast carcinomas were detected and 49 patients (31.0%) died. Low eGFR at the time of diagnosis of malignancy, advanced age at transplantation, advanced age at the time of diagnosis of malignancy and male sex were significantly higher in the mortality group (p <0.05). Conclusion: Post-transplant malignancies are a significant cause of graft and patient loss. Because of the higher incidence and more aggressive course in the transplant patient group, patients should be included in appropriate screening programs, should be informed on whole body skin examination and every suspicious lesion must be biopsied and early diagnosis and treatment should be planned. Keywords: Renal transplantation, malignancy, posttransplant malignancy, prognosis, mortality