Longitudinal changes in kidney function and its long-term impact in childhood cancer survivors: a single-center...

Childhood cancer survivors (CCSs) are at a high risk of developing chronic kidney disease (CKD) as a late effect. In this study, we aimed to analyze longitudinal trends in kidney function in CCSs shortly after cancer treatment and its long-term impact.

We conducted a single-center retrospective cohort study of children aged 0-18 years treated for cancer between January 2011 and December 2021. The patients were classified as renal insufficiency (RI) group or normal renal function group, depending on whether they maintained estimated glomerular filtration rate based on creatinine (eGFRcr) ≥ 90 mL/min/1.73 m² during follow-up. The RI group was subdivided into progressive RI group and transient RI group, depending on whether eGFRcr recovered to ≥90 mL/min/1.73 m² at the last follow-up.

Of the 135 patients, 86 (64 %) were classified into the normal group and 49 (36 %) into the RI group (20 transient and 29 progressive RI). The normal and transient RI groups showed a significant increase in eGFRcr between the time of diagnosis and 1 year after diagnosis (annual percentage change: +16.4 % and +13.7 %, respectively), whereas the progressive RI group showed a decrease (-12.2 %). Over the 5-year follow-up period after diagnosis, the RI group showed significantly lower eGFRcr at all time points (P < 0.01), and both the progressive and transient RI groups maintained eGFRcr levels below those of the normal group.

Long-term decline in eGFRcr was observed even after recovery from temporary kidney injury, suggesting the importance of long-term follow-up of kidney function in CCSs.