All-cause and cancer-specific overall survival in kidney transplant recipients with pre-transplant malignancies in a German cohort

Kidney insufficiency and immunosuppression are well established contributors of tumor development, both before and after kidney transplantation. Patients with pre-transplant malignancies (PTM) are at risk of tumor recurrence and of the development of an unrelated tumor after transplantation. In this retrospective study of a German patient cohort, we analyzed 1089 patients that underwent kidney transplantation to determine the frequency, recurrence rate and overall survival of patients with pre-existing tumors across a 10-year period. PTM were found in 5.79% of the patients and appeared at a mean time of 7.39 (SD 6.8) years before transplantation. The tumors were most frequently of urologic (41.43%) origin, followed by malignancies of the skin (25.71%) and gynecologic tumors (10%). Tumor recurrence was observed in one case (1.6%) where the patient died of metastatic spinocellular carcinoma. Patients with pre-existing malignancies had a statistically significantly worse overall survival compared to transplant recipients without tumors (HR = 2.71, 95% CI 1.49–4.969). However, these differences could be entirely ascribed to the age (HR = 1.06, 95% CI 1.04–1.08) and gender (HR = 1.67, 95% CI 1.11–2.52) of the patients. We found that there was no difference in cancer-specific mortality or posttransplant cancer rate between patients with and without pre-existing malignancies (HR = 0.94, 95% CI 0.21–4.26).