Basal renal function reserve and mean kidney dose predict future radiation-induced kidney injury in stomach cancer patients

Abstract

Adjuvant chemoradiotherapy (CRT) improves the survival in patients with locally advanced stomach cancer. The kidneys are the major dose-limiting organs for radiotherapy (RT) in upper abdominal cancers. We aimed to evaluate the impact of adjuvant CRT on renal function of patients with stomach cancer. Fifty-nine stomach cancer patients who underwent postoperative CRT were included. Demographic parameters (age, gender), and basal and 12th-month biochemical parameters were recorded. Mean kidney dose (MKD) administered was determined. Estimated glomerular filtration rate (eGFR) was calculated by modification of diet in renal disease formula. Fifty-nine patients were recruited (age 60.8 ± 11.9years; female/male 25/34; follow-up duration 15.6 ± 9.8months). Twenty-one patients (35.6%) had basal eGFR <90ml/min/1.73m(2). When the basal and 12th-month eGFR was compared, eGFR decreased in 27 patients (45.8%), whereas eGFR remained stable in 32 (54.2%) patients. Cox regression analyses revealed that a MKD ≥1,500cGy and basal eGFR <90ml/min/1.73m(2) significantly increased the risk of a decreased eGFR at 12th month (HR = 2.288, 95% CI 1.009-5.188, p = 0.048 and HR = 2.854, 95% CI 1.121-7.262, p = 0.028, respectively). MKD ≥1,500cGy and a basal eGFR <90ml/min/1.73m(2) significantly increased the risk of a decreased eGFR at 12th month. We suggest that patients with stomach cancer be evaluated for their basal renal reserve prior to RT, and it may be more convenient to further minimize the dose to the kidneys with more sophisticated RT techniques in patients with stomach cancer, more specifically in patients with decreased renal reserve.