The purpose of the present prospective study was to evaluate the significance of geriatric conditions measured by a comprehensive geriatric assessment (GA) for the prediction of the risk of high-grade acute radiation-induced toxicity.

A total of 314 prostate cancer patients (age ≥ 65 years) undergoing definitive radiotherapy at a tertiary academic center were included. Prior to treatment, patients underwent a GA. High-grade toxicity was defined as acute toxicity grade ≥ 2 according to standard RTOG/EORTC criteria. To analyze the predictive value of the GA, univariable and multivariable logistic regression models were applied.

A total of 40 patients (12.7%) developed acute toxicity grade ≥ 2; high grade genitourinary was found in 37 patients (11.8%) and rectal toxicity in 8 patients (2.5%), respectively. Multivariable analysis revealed a significant association of comorbidities with overall toxicity grade ≥ 2 (odds ratio [OR] 2.633, 95% confidence interval [CI] 1.260–5.502; p = 0.010) as well as with high-grade genitourinary and rectal toxicity (OR 2.169, 95%CI1.017–4.625; p = 0.045 and OR 7.220, 95%CI 1.227–42.473; p = 0.029, respectively). Furthermore, the Activities of Daily Living score (OR 0.054, 95%CI 0.004–0.651; p = 0.022), social status (OR 0.159, 95%CI 0.028–0.891; p = 0.036), and polypharmacy (OR 4.618, 95%CI 1.045–20.405; p = 0.044) were identified as independent predictors of rectal toxicity grade ≥ 2.

Geriatric conditions seem to be predictive of the development of high-grade radiation-induced toxicity in prostate cancer patients treated with definitive radiotherapy.