Longitudinal kidney function outcome in aging testicular cancer survivors

Purpose: Testicular cancer survivors (TCSs) have increased risk of reduced kidney function related to treatment burden, but longitudinal studies of renal outcome in aging TCSs have been lacking. This longitudinal study describes age- and treatment-related kidney function changes in TCSs compared to a comparison group from the general population.Patients and methods: Estimated glomerular filtration rate (eGFR) was determined in blood samples from Norwegian TCSs (diagnosed 1980-1994) and surveyed median 11, 19 and 26 years since diagnosis (Survey1 [N = 1273], 2 [N = 849] and 3 [N = 670]) defining four treatment groups; Surgery only, Radiotherapy (RT) only, Cisplatin-based chemotherapy (CBCT) ≤850 mg and High CBCT/RT >850 mg cisplatin or any combination of CBCT with RT. A comparison group was constructed from similarly aged men who participated in a population-based health survey. By multiple linear regressions and generalized mixed models for repeated measurements, we studied difference in eGFR between TCSs and the comparison group for all TCSs combined and stratified by treatment modality.Results: At Survey 1, the kidney function for the youngest TCSs combined versus the comparison group was significantly reduced by mean six units (mL/min/1.73 m²) with further decline to mean 12 units at Survey 3. The kidney function was significantly reduced in all treatment groups with the largest differences emerging for TCSs from the High CBCT/RT Group, thus indicating a deteriorating impact of high cumulative doses of cisplatin.Conclusion: Collated to the comparison group, the kidney function in TCSs became increasingly impaired during nearly three post-treatment decades, related to the treatment modality. Early detection and intervention of kidney dysfunction is important to reduce the risk of TCSs' long-term morbidity and mortality related to nephrotoxicity, such as cardio-vascular diseases.