Transabdominal Ultrasonography-Defined Optimal and Definitive Bladder-Filling Protocol With Time Trends During Pelvic Radiation for Cervical Cancer

Abstract

Purpose:Advanced radiotherapy techniques have emphasized on the importance of accurate target volume localization and delineation. The aim of this study was to determine time taken to achieve moderate bladder volume under physiological conditions, using transabdominal ultrasound.Materials and Methods:Patients with cervical cancer undergoing radical radiation with or without concomitant chemotherapy underwent serial ultrasound to estimate bladder filling. With a strict bladder protocol of consuming 1000 mL of water orally over 30 minutes after emptying the bladder, ultrasound was done after 45 minutes from bladder emptying time and repeated at 15-minute interval till 300 (25) mL filling was achieved and repeated every week.Results:Forty-six patients with weekly ultrasound for bladder-filling documentation were evaluated. The mean (standard deviation) bladder volume measured at 45 minutes was 220 (93), 210 (95), 195 (91), 195 (96), and 190 (85) mL (average: 200; median: 195 mL) for the first to fifth week, respectively, and the mean (standard deviation) volume at 75 minutes was 300 (95), 310 (80), 290 (80), 295 (80), and 285 (70) mL (average: 295; median: 300 mL). The mean (standard deviation) time for bladder filling to 300 mL in the first, second, third, fourth, and fifth week was 57 ( 13.5), 67 (16.6), 66 (16.7), 66 (15.5), and 69 (17.1) minutes, respectively.Conclusion:Bladder filling to a definitive moderate volume at a reasonably fixed time period in each week of radiation is well tolerated, feasible, and measurable by weekly transabdominal ultrasound measurements.

Overview of patient preparation strategies to manage internal organ motion during radiotherapy in the pelvis

“…Umesh et al performed a cohort study of patients treated with cervical radiotherapy. 47 They found that a 300 mL bladder volume was tolerable throughout treatment and was achieved after a mean time of 65 minutes following bladder emptying and administration of 1,000 mL of water. A further benefit from ultrasound is the potential to reduce radiation dose from additional CBCT scans.…”

“…This approach is supported by an RCT by Mullaney et al of two different drinking protocols in prostate radiotherapy. The group found that 540 ml (3 cups of water over 10 minutes) was associated with better reproducibility of bladder volume as assessed by bladder ultrasound than 1080 ml (6 cups of water over 10 minutes) [42]. Studies of ultrasound bladder scanning have reported improved consistency of bladder volume during prostate radiotherapy [43][44][45].…”