A randomized trial comparing bladder volume consistency during fractionated prostate radiation therapy

Area of Science:

• Radiation Oncology
• Medical Physics
• Urology

Background:

• Organ motion during prostate radiation therapy (RT) causes variations in target and organ at risk positioning.
• Consistent bladder volume (BV) is crucial for accurate radiation delivery.
• Evidence-based bladder-filling instructions are needed to standardize BV.

Purpose of the Study:

• To compare two bladder-filling protocols (540 mL vs. 1080 mL) for consistency in bladder volume during prostate RT.
• To assess the impact of bladder-filling protocols on genitourinary (GU) and gastrointestinal (GI) toxicity.
• To evaluate patient satisfaction and quality of life (QoL) related to bladder-filling instructions.

Main Methods:

• A prospective randomized controlled trial involving 110 patients undergoing prostate RT.
• Patients were assigned to either a 540 mL or 1080 mL water intake protocol.
• Bladder volumes were measured using ultrasound at planning and during treatment; toxicity and QoL were assessed.

Main Results:

• The 540 mL protocol demonstrated significantly less variation in bladder volume compared to the 1080 mL protocol (median 76 mL vs. 105 mL).
• Larger initial bladder volumes correlated with greater variations during RT.
• No significant differences in acute or late GU/GI toxicity, patient comfort, or QoL scores were observed between the groups.

Conclusions:

• A 540 mL bladder-filling protocol leads to reproducible bladder volumes throughout prostate radiation therapy.
• This protocol can be implemented without compromising patient quality of life or increasing treatment toxicity.
• Standardizing bladder volume through simple hydration instructions improves treatment consistency.