# Renal Function Deterioration in Postoperative (Adjuvant) Chemotherapy for Colon Cancer—Real-Life Data

## TL;DR

This study finds that older age and diabetes increase kidney risk during colon cancer chemotherapy, but early kidney decline doesn't predict future issues.

## Contribution

The study identifies age and diabetes as risk factors for kidney function decline during chemotherapy and challenges the need to shorten treatment based on early mild kidney injury.

## Key findings

- 54.4% of patients experienced kidney function deterioration after 3 months of chemotherapy.
- Older age (≥70 years) and diabetes were significant risk factors for early kidney decline.
- Early kidney function decline did not predict further deterioration with continued chemotherapy.

## Abstract

We retrospectively evaluated the estimated glomerular filtration rate (eGFR) in 145 patients with colon cancer after 3 months of adjuvant chemotherapy (aCTH) and the overall renal risk associated with this regimen continuation up to 6 months. A decrease of at least 1.5 mL/min/1.73 m2 in eGFR after three months and 3.0 mL/min/1.73 m2 after six months were considered relevant regarding kidney-related cardiovascular risk. Our findings highlight that age ≥ 70 years and diabetes were risk factors for deterioration in kidney function during the first three months of therapy. However, the decline during the first three months did not allow the prediction of further changes under continued aCTH. Thus, our research has the potential to influence clinical practice, suggesting that development of mild kidney injury should not be an argument for shortening aCTH to 3 months, even in patients with diabetes or those older than 70 without preexisting chronic kidney disease.

The knowledge concerning mild-to-moderate renal toxicity of adjuvant chemotherapy (CTH) in colon cancer patients is scarce. We retrospectively evaluated changes in the estimated glomerular filtration rate (eGFR) after three months of adjuvant treatment and the overall renal risk of the 6-month regimen in 145 patients who completed three months of therapy at three oncological centers. A decrease in eGFR of at least 1.5 mL/min/1.73 m2 after three months and 3.0 mL/min/1.73 m2 after six months was considered relevant in terms of kidney-related cardiovascular risk. Out of 114 patients who completed a 6-month regimen, kidney function deterioration occurred in 62 (54.4%) after 3 months and in 54 (47.4%) after 6 months. Age ≥ 70 years (RR = 2.66; 95% CI: 1.15–6.16) and diabetes (RR = 2.52; 95% CI: 0.98–6.45) were risk factors for kidney outcomes during the first three months of CTH. However, renal function decline during the first three months did not increase the risk of further deterioration on CTH continuation. In conclusion, older age and diabetes are factors increasing the risk of renal function deterioration during adjuvant CTH in colon cancer patients without preexisting chronic kidney disease. However, the decline during the first three months does not allow for predicting further changes under continued adjuvant therapy.