Impact of bladder volume on acute genitourinary toxicity in intensity modulated radiotherapy for localized and locally advanced prostate cancer.

Abstract

To evaluate the effect of changes in bladder volume during high-dose intensity-modulated-radiotherapy (IMRT) of prostate cancer on acute genitourinary (GU) toxicity and prospectively evaluate asimple biofeedback technique for reproducible bladder filling with the aim of reducing acute GU toxicity. One hundred ninety-three patients were trained via abiofeedback mechanism to maintain apartially filled bladder with areproducible volume of 200-300 cc at planning CT and subsequently at each fraction of radiotherapy. We prospectively analyzed whether and to what extent the patients' ability to maintain acertain bladder filling influenced the degree of acute GU toxicity and whether cut-off values could be differentiated. We demonstrated that the ability to reach areproducible bladder volume above athreshold volume of 180 cc and maintain that volume via biofeedback throughout treatment predicts for adecrease in acute GU toxicity during curative high-dose IMRT of the prostate. Patients who were not able to reach apartial bladder filling to that cut-off value and were not able to maintain apartially filled bladder throughout treatment had asignificantly higher risk of developing ≥grade2 GU acute toxicity. Our results support the hypothesis that abiofeedback training for the patient is an easy-to-apply, useful, and cost-effective tool for reducing acute GU toxicity in high-dose IMRT of the prostate. Patients who are not able to reach and maintain acertain bladder volume during planning and treatment-two independent risk factors-might need special consideration.