De Novo Malignancies Following Renal Transplantation: Experience of a Single Center

Abstract

Background: Many authors have related an increased risk for malignancies in organ transplant recipients. This study describes de novo malignancies after kidney transplantation at a single center. Material and Methods: This investigation includes the data from 1,388 patients (870 men, 518 women) who received a renal allograft from September 1, 1976 to January 1,1990 and were followed up until July 11990 during an average follow-up of 3.97 ± 2.80 years. These files were retrospectively studied for malignancies diagnosed after kidney transplantation. We used the Saarland Tumor Registry to calculate the expected number of neoplasias for an equivalent patient group. As immunosuppressive regimen we first used a scheme based on azathioprine, then one based on high-dosed cyclosporine, and last a low-dosed cyclosporine-based one. Furthermore we analyzed the influence of sex and age at transplantation, dialysis period prior to transplantation, number of transplantations, and underlying pathologies on the incidence of malignancies. Results: A total number of 35 patients developed a malignant tumor, which compared to an expected number of 16.12 ± 3.99 malignancies represents an increase in incidence by a factor of 2.2 and proved to be highly significant. No significant difference in the global incidence of malignancies could be shown between the 3 immunosuppression schemes. Furthermore we didn’t find any factors that suggested an influence of sex, dialysis period prior to transplantation or repeated transplantations on the incidence of malignant tumors. On the other hand, a comparison with our global patient group showed that patients who later developed a malignant tumor were significantly older at the time of transplantation and also had a significantly increased proportion of pyelonephritis as an underlying pathology that led to renal failure. The most frequent tumors seen were malignant lymphomas, skin cancers and urological or gynecological malignancies. Conclusions: Our study confirms the increased risk for malignancies after renal transplantation and strengthens the need for a close and regular examination of these patients with special attention to neoplasias.