Malignancy in renal transplant recipients, incidences, and risk factors: More than three decades of experience

Objectives: This retrospective study was performed to report the incidence of malignancy in renal transplant recipients and also to identify the risk factors causing it. Material and Methods: We have studied 506 renal transplant recipients , follow-up patients from 1989 to 2023 at a single center, Dubai Hospital. Results: The mean age of renal transplant recipients at the time of transplant in our study population was 55 ± 21 years and 39 ± 14.93 years, respectively, also the predominant gender was male (64.62%, n =327). Diabetic nephropathy (21.93%, n=111), chronic glomerulonephritis (21.14%, n =107), and obstructive uropathy (8.69%, n =44) were the three most common etiologies of chronic kidney disease in transplant recipients. About 94.87% ( n =480) of transplant recipients had a living donor; also, 15 (2.96%) patients had a history of multiple renal transplants. Incidence of CMV (cytomegalovirus), HCV (Hepatitis C virus), BK virus (BKV), HBV (Hepatitis B virus) infections was 13.83% ( n =70), 12.05% ( n =61), 4.94% ( n =23), and 2.17% ( n =11), respectively. Prednisolone was the most common immunosuppressive used in 98.81% ( n =500), followed by cyclosporine (66%, n =334), mycophenolate mofetil (60.67%, n =307), tacrolimus (27.47%, n =139), sirolimus (12.45%, n =63), and everolimus (0.39%, n =2). Triple immunosuppressive was used in 91.30% ( n = 462). Biopsy-proven acute rejection (BPAR) is observed in 23.12% (n=117) of transplant recipients. Incidence of malignancy in renal transplant recipients is 8.10% ( n =41), 60.9% ( n =25) of whom were male. The hematological malignancies were commonest ( n =9, 21.9%) in our study population that include post-transplant lymphoproliferative disorder and multiple myeloma in 7 (17.07%) and 2 (4.87%) patients, respectively, followed by skin, urological (14.6%, n =6 each), and colorectal cancer (12.19%, n =5), also other low incidence malignancies involving lung ( n =2, 4.87%), breast ( n =2, 4.87%), central nervous system ( n =2, 4.87%), genital organs ( n =2, 4.87%), endocrine( n =2, 4.87%), liver ( n =2, 4.87%), prostate ( n =1, 2.43%), and oral cavity cancer ( n =1, 2.43%). Prednisolone (85.36%, n =35), cyclosporine (60.97%, n =25), and mycophenolate mofetil (56.09%, n =23) were common immunosuppressive used in malignancy affected renal transplant recipients; also, CMV, HCV infection, and BPAR was observed in 17.07% ( n =7), 14.63% ( n = n =6), and 19.51% ( n =8) patients. Seven (17.07%) patients died due to malignancy related complications. Conclusion: Overall survival rate of renal transplant recipients without malignancy in our study population is 100%, 95%, and 79% at 1, 5, and 10 years, respectively, and 97%, 92%, and 87% in those with malignancy, respectively. Multivariate analysis reveals that cyclosporine usage poses a greater risk of developing cancer, whereas induction agents and maintenance immunosuppression, including antimetabolites, corticosteroids, and mammalian target of rapamycin inhibitors, were not associated with a high risk of developing post-transplant malignancy.