De Novo Malignancies After Kidney Transplant: Where Do We Stand and Does the Head and Neck Region Require More Caution?

ABSTRACT

OBJECTIVES: The aim of this study was to investigate the characteristics of de novo malignancies arising in kidney transplant recipients followed in a tertiary hospital in Turkey and to examine the tumors in the head and neck region as a subgroup. MATERIALS AND METHODS: Data from kidney transplant recipients treated at our institution between January 2010 and July 2022 were retrospectively analyzed in this single-center study. Data regarding malignancies were noted according to the pathologists' reports. In situ malignancies and those arising after graft loss were not evaluated. RESULTS: The study population comprised 231 patients (165 men; 71.4%) with a median follow-up of 11 years (2853 patient-years). The recipients had a higher cancer risk than the general population (standardized incidence rate = 3.04; 95% CI, 1.82-4.26). Thirty de novo malignant tumors were detected in 24 patients (10.4%). The mean age at diagnosis of cancer was 54.88 ± 11.44 years. The median time from transplant to cancer diagnosis was 11.5 years (range, 7-18.8 y). Nonmelanoma skin cancers (56.7% of all tumors) were the most common malignancies. Twenty-two lesions (73.3%) that developed in 17 patients (7.4%) were localized to the head and neck region 15 (68.2%) were cutaneous and 7 (31.8%) were noncutaneous. The median time from transplant to head and neck cancer diagnosis was 12 years (range, 7.5-17.5 y). Mortality rate was higher in cancer patients (10 [41.7%] vs 17 [8.2%]; P < 0.01). CONCLUSIONS: The incidence of de novo malignancy in kidney transplant recipients was relatively higher compared with previous data. Nonmelanoma skin cancers were the most common type. Three-quarters of all lesions were in the head and neck region, and two-thirds were of cutaneous origin.