A service evaluation on the influence of daily micro-enemas on interfraction prostate motion and acute bowel side effects in patients receiving external beam radiotherapy to the prostate

Abstract

Purpose: To evaluate the effect that daily micro-enemas had on interfraction prostate motion and acute bowel side effects during external beam radiotherapy (EBRT) to the prostate. Methods: 30 patients were recruited into two groups. 15 patients had used daily micro-enemas and 15 had not. Interfraction prostate motion was determined as the prostate shift relative to bony anatomy on each patient's daily cone beam computed tomography (CBCT) scans. These shifts were analysed for each of the patient's 37 treatments, therefore a total of 1100 fractions were included in total, with three sets of shifts being analysed for each fraction. These shifts were representative of the left/right (X), superior/inferior (Y) and anterior/posterior (Z) movements. Patients' side effects were observed by analysing changes to weekly bowel Radiation Therapy Oncology Group (RTOG) assessment scores to determine if a difference was observed between the two groups. Each patient had a baseline bowel RTOG assessment, followed by seven weekly RTOG scores. Therefore, each patient had eight scores making a total of 240 scores included in the service evaluation. Results: Interfraction prostate motion was significantly reduced in the enema group in the left/right (X) and anterior/posterior (Z) directions (p<0.05). In the superior/inferior (Y) direction the non-enema group had significantly smaller moves than the enema group (p<0.05). Bowel side effects were found to be significantly lower in the enema group when compared to the non-enema group (p<0.05). Conclusion: This service evaluation concluded that the use of daily micro-enemas was an effective way to reduce interfraction prostate motion and side effects in these groups of patients. A further prospective randomised study is advocated to validate these results before implementing a change in clinical protocols.