Occurrence of malignancies after kidney transplantation in adults: Slovak multicenter experience.

Malignancies are one of the three major causes of renal recipient´s death with a functioning graft after cardiovascular diseases and infections. Among the variety of risk factors, including conventional and specific to transplant recipients, the duration of immunosuppressive therapy, the intensity of therapy, and the type of immunosuppressive agent all have an impact on development of post-transplant malignancy. The aim of our retrospective study was to document the incidence, the type of malignancies, the patient/graft survival in the group of kidney transplant recipients in Slovak Republic, and to identify the factors which influenced the outcome. We analyzed the data of 1421 patients who underwent renal transplantation from deceased or living donors in the period from 2007 to 2015 in the Slovak transplant centers. The incidence of malignant tumors was 6%, the malignancy was diagnosed in 85 patients at the age of 54.1 ± 9.8 years, more frequently in men (68.2 %; P < 0.0001). The mean time of malignancy occurrence was 45 months after transplantation. The most frequent malignancies were skin cancers- basal cell carcinoma (BCC) in 17.6%, squamous cell carcinoma (SCC) in 8.2%, and malignant melanoma (MM) in 2.4% of patients, followed by non-skin tumors such as renal cell carcinoma (RCC) in 16.5%, cancer of colon in 12.9%, prostatic cancer in 9.4%, breast cancer in 9.4%, cancer of lung in 7.1%, post-transplant lymphoproliferative disease (PTLD) in 2.4%, cancer of urine bladder in 2.4%, and cancer of sublingual gland in 1.17% of patients. Surgical treatment was used in 40% of patients, chemotherapy in 7.1%, radiotherapy in 2.4%, treatment with biological agents in 15.3%, combined therapy in 29.4% and palliative treatment in 5.9% of patients. 55.3% of patients underwent conversion from other immunosuppressive agents into mTORi at the time of malignancy occurrence. The remission was achieved in 48.2% of patients, 28.2% of patients were in the oncology treatment in the end of the year 2015, and 23.5% of patients died. There was no difference in the kidney function at the time of malignancy occurrence (s-creat 133.7 ± 59.8 µmol/l) and one year later (s-creat 131.1 ± 47.9 µmol/l) (P = 0.7768). The patients after successful treatment more frequently suffered from BCC (P = 0.0140), did not undergo palliative treatment (P = 0.0033), but were more frequently treated surgically (P < 0.0001).