ESTRO 2025 - Abstract Book

S1493

Clinical – Mixed sites & palliation

ESTRO 2025

1522

Digital Poster Contrast-Associated Acute Kidney Injury Among Oncology Patients Undergoing CT Radiotherapy Planning Scans: A Retrospective Cohort Study Bhurint Siripanthong 1,2 , Edward Chandy 2 1 Department of Medicine, Imperial College Healthcare NHS Trust, London, United Kingdom. 2 Department of Clinical Oncology, University Hospitals Sussex NHS Foundation Trust, Brighton, United Kingdom Purpose/Objective: Aversion to contrast use may limit CT radiotherapy planning. Contrast-Associated Acute Kidney Injury (CA-AKI) incidence is 2 – 9% (1-2) , but its risk in this context is unclear. This study evaluates AKI risk in oncology patients undergoing contrast-enhanced CT scans. Material/Methods: Patients undergoing contrast or non-contrast radiotherapy planning CT scans at the Sussex Cancer Centre, Royal Sussex County Hospital, UK, between December 2018 and January 2020, were screened for study inclusion. The inclusion criteria were: (1) a creatinine level measured within 3 months pre-scan and (2) a creatinine level measured 1 – 21 days post-scan. Patients on renal replacement therapy were excluded. The primary outcome was AKI incidence, defined as a creatinine rise of ≥25% from baseline or an absolute increase of 44µmol/L, whichever was lower. Secondary outcomes included (1) AKI severity, (2) AKI resolution, and (3) 3-month post-scan mortality. Two-tailed unpaired t-tests were used for parametric data comparisons, while Fisher's exact tests were applied for proportions. Results: Out of 1,135 patient records screened (445 contrast and 690 non-contrast), 281 patients met the criteria: 141 in the contrast group and 140 in the non-contrast group. The incidence of AKI did not differ significantly between groups (contrast vs non-contrast, 2.84% vs. 5.00%, p = 0.54). Median AKI severity was stage 1 in both groups, with most patients achieving full resolution of renal impairment (100% vs. 85.7%, p = 1). Three-month post-scan mortality was lower in the contrast group (0% vs. 57.1%, p = 0.52). The baseline characteristics differed significantly between the two cohorts. Compared to the non-contrast group, patients in the contrast group were younger (60.89 ± 10.17 vs. 69.64 ± 10.77 years, p < 0.0001), had higher baseline eGFR (91.72 ± 15.30 vs. 84.04 ± 21.07 mL/min/1.73m 2 , p = 0.0006), and were less frequently undergoing palliative radiotherapy (4.26% vs. 57.14%, p < 0.0001). Subgroup analysis of patients receiving radical radiotherapy revealed persistent baseline differences (contrast vs. non-contrast: age (years) 60.94 ± 10.17 vs. 65.62 ± 10.38, p = 0.0070; baseline eGFR (mL/min/1.73m 2 ) 91.22 ± 15.31 vs. 85.19 ± 20.25, p = 0.0325). AKI incidence remained similar between the groups (2.96% vs. 1.89%, p = 1), with all affected patients achieving full resolution and surviving at three months post-scan. Conclusion: There was no excess AKI risk with contrast exposure; CA-AKI incidence was 2.84%. Most AKIs were mild, with full resolution in nearly all patients. Important confounders include concomitant systemic anti-cancer therapies, age, and baseline eGFR. Further studies with matched or randomized cohorts are needed.

Keywords: Contrast-Associated Acute Kidney Injury

References: [1] Song W, Zhang T, Pu J, Shen L, He B. Incidence and risk of developing contrast-induced acute kidney injury following intravascular contrast administration in elderly patients. Clin Interv Aging 2014;9:85 – 93. https://doi.org/10.2147/CIA.S55157.