De Novo Malignant Neoplasms in Renal Transplant Patients.

OBJECTIVES: The aim of this study was to evaluate the incidence of posttransplant malignancy in kidney transplant patients and investigate the clinical and histopathologic features of these patients.

MATERIALS AND METHODS: We retrospectively reviewed information on donor and recipient characteristics, patient and graft survival, and cancer incidence after transplant for 867 kidney transplant patients. Patients with neoplasms prior to transplant were excluded. A follow-up study estimated cancer incidence after transplant.

RESULTS: Neoplasms were diagnosed in 59 patients (6.8%), 41 men and 18 women; 22 (37.3%) had skin tumors, 19 (32.2%) had solid tumors, 10 (16.9%) had posttransplant lymphoproliferative disorders, and 8 (13.6%) had Kaposi sarcoma. The mean age at the time of malignant tumor diagnosis was 42.7 ± 13.6 years, and statistically significant differences were found between tumor groups (P < .01). The average latency period between transplant and diagnosis of malignant tumors was 99.8 ± 56.9 months for solid tumors, 78.4 ± 52 months for skin tumors, 64.5 ± 48.8 months for posttransplant lymphoproliferative disorders, and 13.5 ± 8.8 months for Kaposi sarcoma, with significant difference found between tumor groups (P < .01). Ten patients (16.9%) had more than 1 malignant tumor. Eighteen patients died, with a mean time to death of 31.5 ± 22.8 months after tumor diagnosis. A significant positive association was found between survival and the number of tumors (P = .001); 5-year survival after tumor diagnosis was 81% and 40% for patients with 1 malignant tumor and patients with more than 1 malignant tumor, respectively.

CONCLUSIONS: Malignancy is a common cause of death after renal transplant. Early detection and treatment of posttransplant malignancies is an important challenge. Screening these patients for malignancies posttransplant is crucial, and efforts should be directed to define effective immunosuppressive protocols that are associated with a lower incidence of malignancy.