Accumulated bladder wall dose is correlated with patient-reported acute urinary toxicity in prostate cancer patients treated with stereotactic, daily adaptive MR-guided radiotherapy

•Dose accumulation provides estimation of the dose delivered with MR-guided SBRT.•Accumulated bladder (wall) dose was calculated for 130 prostate cancer patients.•Bladder (wall) dose was correlated with patient-reported acute urinary toxicity.•Mean dose to the bladder (wall) showed the highest correlation.•Based on AUC, bladder wall parameters showed stronger correlations with the outcome.