Malignancies after kidney transplantation: results of a 34-year population-based study

BACKGROUND . Cancer is the second most common cause of mortality and morbidity in kidney transplant recipients (KTRs) after cardiovascular diseases (CVDs). KTRs have at least twice the risk of developing cancer or dying from it compared to the general population. THE AIM: to calculate the standardized incidence ratio (SIR) and mortality ratio (SMR) of malignancies in KTRs registered at Municipal Clinical Hospital № 52 of the Moscow Healthcare Department and to determine independent risk factors for MN. PATIENTS AND METHODS. From January 1, 1989 to December 31, 2023, we followed 2146 KTRs registered at Municipal Clinical Hospital №52 of the Moscow Healthcare Department, in whom 14.4 % (n=310) MN were detected. In the malignancies group, the most common were non-melanoma skin cancer (NMSC) 30.3 % (n=91) and kidney cancer 11.3 % (n=41), 37.7 % (n=117) of patients died, of which 46.2 % (n=54) died directly from this cause. RESULTS. In kidney transplant recipients, the overall risk of malignancies was approximately three times higher than in the Russian population (SIR 2.85, 95 % CI: 2.4–3.2, P<0.05). The highest incidence was observed for kidney cancer SIR 5.8 (95 % CI: 4.0–7.5, P<0.05), non-melanoma skin cancer (NMSC) SIR 5.8 (95 % CI: 4.6–6.9, P<0.05), melanoma SIR 3.99 (95 % CI: 3.5–4.3, P<0.05), cervical cancer SIR 3.0 (95 % CI: 1.5–4.4, P<0.05), thyroid cancer SIR 2.1 (95 % CI: 1.4–2.9, P<0.05) and chronic lymphocytic leukemia (CLL, ICD codes: C91.1–9) SIR 10.3 (95 % CI: 4.5–16.0, P<0.05). Mortality from all types of malignancies after kidney transplantation slightly exceeded the general population mortality in the Russian Federation (SMR 1.3, 95 % CI: 1.1–1.4, P<0.05). The highest mortality after transplantation was from NMSC SMR 51.4 (95 % CI: 25.3–77.4, P<0.05) and melanoma SMR 8.6 (95 % CI: 2.5–14.6, P<0.05). CONCLUSIONS. The overall incidence of malignancies after kidney transplantation in patients registered at Municipal Clinical Hospital №52 of the Moscow Healthcare Department in 1989–2023 is almost 3 times higher than the general population incidence in the Russian Federation (overall SIR = 2.85 (95 % CI: 2.4–3.2, P<0.05). Mortality from malignancies (overall SMR = 1.3 (95 % CI: 1.1–1.4, P<0.05)) is slightly higher than the general population incidence. A possible reason for the almost twofold difference between the incidence and mortality from malignancies in the Russian Federation may be the high risk of competing causes of mortality in KTRs, especially CVDs.