Risk of post-transplant malignancy: a single center retrospective comparative study between everolimus and mycophenolate in kidney transplant recipients

Background: While cardiovascular and infection-related mortality have improved with transplant care, malignancy-related deaths have shown no significant change. Post-transplant malignancy risk is attributed to immunosuppression but the effect on graft outcome and cancer development is not clearly determined. Methods: A monocentric-retrospective study on 159 single or double kidney transplant recipients (KTRs) followed at the Padova University Hospital, Kidney-Pancreas Transplant Ambulatory Unit, who underwent kidney transplantation between January 2015 and December 2018, was performed to investigate the immunosuppression role in cancer development via comparison between patients treated with mTORi (everolimus) and with mycophenolate (mean observation 7 years). Cancer trend, cancer type, mortality and graft survival rate in KTRs receiving different immunosuppression protocols were also investigated. Results: 54 patients had de novo cancers, most common skin cancer (non-melanoma) ; no significant association was found between the 2 groups of KTRs as for de novo malignancies development. Multivariable logistic regression indicated age, HCV and history of pretransplant malignancy predictors of cancer development. Patients and graft survival during the follow-up were higher in mycophenolate group, while the rejection rate was lower although not significant in the everolimus group. mTORi was not associated with de novo significant cancer reduction vs mycophenolate. Older age, HCV and history of pretransplant cancer were associated with cancer development. Conclusion: Our study suggests that older KTRs are more likely to develop post-transplant malignancies indicating that individualized minimization of immunosuppression may be considered in selected older KTRs after careful assessment of the balance between malignancy risk and graft outcomes.