Conversion to mammalian target of rapamycin inhibitors in kidney transplant recipients with de novo cancers

OBJECTIVE To investigate the impact of mammalian target of rapamycin (mTOR) inhibitor conversion together with minimization of calcineurin inhibitor on allograft outcome and patient survival in kidney transplant recipients with post-transplant cancers. METHODS A retrospective study of all kidney transplant recipients diagnosed to have post-transplant cancers between the period 1/1/1994 and 30/6/2015. Patients were divided into 2 groups: mTOR inhibitor group and non-conversion group. Outcome included allograft function, patient survival, graft survival, acute rejection and cancer recurrence. RESULTS 115 patients (56 in mTOR inhibitor group and 59 in non-conversion group) were analyzed. Median follow up was 28 months (range: 1 month - 20 years). The allograft function at 1-year remained similar between both groups. There was no significant difference in the patient survival, graft survival and rejection free survival between both groups. More patients in the non-conversion group developed recurrence of cancers than mTOR inhibitor group but statistically not significant. CONCLUSIONS Use of mTOR inhibitors together with calcineurin inhibitor minimization offer a reasonable option in kidney transplant recipients who developed post-transplant cancers in view of stable renal function, low rejection rate and low cancer recurrence rate.