Conversion from Calcineurin Inhibitor-Based Immunosuppression to Mycophenolate Mofetil in Monotherapy Reduces Risk of De Novo Malignancies After Liver Transplantation

Background: Immunosuppression increases the risk of malignancy in liver transplant recipients. The potential impact of mycophenolate mofetil monotherapy on this risk has not been studied. Material/Methods: The incidence and risk factors for de novo malignancies of 392 liver transplant recipients with a survival higher than 3 months and a mean follow-up of 8.5 years were studied. Results: De novo malignancies were diagnosed in 126 patients (32.1%) (64 non-melanoma skin cancer and 81 other malignancies). Sixty-nine patients (18.1%) stopped receiving calcineurin inhibitors and were maintained on mycophenolate mofetil monotherapy. The proportion of time on mycophenolate mofetil monotherapy (obtained after dividing the time on monotherapy by the time until diagnosis of neoplasia/last follow-up) was independently associated with a lower risk of de novo malignancy (HR: 0.16, 95% CI: 0.05-0.48; P=0.001), non-melanoma skin cancer (HR: 0.17, 95% CI: 0.03-0.79; P=0.024), and other malignancies (HR: 0.23, 95% CI: 0.07-0.77; P=0.017). Older age and male sex were also associated with a higher risk of malignancy, and transplantation for hepatocellular carcinoma increased the risk of non-melanoma skin cancer. Conclusions: Mycophenolate mofetil monotherapy is associated with a lower risk of cancer in liver transplant recipients compared with maintenance immunosuppression with calcineurin inhibitors.