Long-term allograft and patient outcomes of kidney transplant recipients with and without incident cancer - a population cohort study.

The excess risk for cancer in kidney transplant recipients is substantial, but the allograft and patient survivals after cancer development are under-studied. This is a population-based cohort study of all primary live and deceased donor kidney transplant recipients in Australia and New Zealand between 1990-2012. The risks of overall graft loss and death with a functioning graft in kidney transplant recipients with and without incident cancer were determined using adjusted Cox regression analysis, with incident cancer considered as a time-varying covariate in the models. In those with incident cancer, types and cancer stage at diagnoses were reported. Of 12,545 transplant recipients followed for a median of 6.9 years (91,380 patient-years), 1184 (9.4%) developed incident cancers at a median of 5.8 years post-transplant. Digestive, kidney and urinary tract cancers were the most common cancer types, although digestive and respiratory tract cancers were more aggressive, with 40% reported as advanced cancers at time of cancer diagnosis. Cancer-related deaths accounted for approximately 80% of recipients with a prior cancer history. Compared with recipients with no prior cancer, the adjusted hazard ratios (HR) for overall graft loss and death with functioning graft were 4.34 (95%CI 3.90, 4.82; p<0.001) and 9.53 (95%CI 8.30, 10.95; <0.001) among those with a prior cancer. Incident cancer after kidney transplantation is a significant risk factor for death with a functioning graft, with the majority of deaths attributed to cancer. A greater understanding of the barriers to screening and treatment approaches following cancer diagnosis may lead to improve survival in kidney transplant recipients with cancer.