Is there enough evidence to standardise bowel and bladder preparation for patients undergoing external beam radiotherapy for prostate cancer? A narrative review

Holmes, Charlie and Kirby, Michael ORCID: 0000-0001-9765-5641 (2022) Is there enough evidence to standardise bowel and bladder preparation for patients undergoing external beam radiotherapy for prostate cancer? A narrative review. [Poster]

Text CH MCK BIRTO22 poster FINAL.pdf - Unspecified Download (504kB) | Preview

Abstract

Introduction Thirty percent of patients with prostate cancer receive external beam radiotherapy (EBRT)1. Improving the therapeutic ratio is the ultimate goal; reducing the dose to organs at risk such as the rectum and bladder, without compromising tumour control2. The prostate moves independently of both rectum and bladder; but reproducing the internal anatomy is possible to a certain extent with bladder/bowel preparation3. However, methods to do so vary. Method A search of databases including Cochrane Library, PubMed, Medline and Scopus was conducted using a PICO framework to systematise and focus the review. Inclusion and exclusion criteria were introduced to tighten focus and narrow down relevant papers to review. The extracted evidence was then analysed, appraised and critiqued using a Preferred Items for Systematic Reviews and Meta-Analyses checklist and CASP methodologies. Results The final fifteen papers included discussed both interfractional and intrafractional movement and a range of bowel/bladder preparations. The metrics for measuring the effectiveness of the preparation used included; set up errors, dose volume histogram assessment, treatment toxicities and disease-free survival. The most common way to analyse the influence of bowel/bladder status was set-up corrections using IGRT. None of the preparation methods identified showed a clear, distinct benefit in terms of reducing set up-errors and there was no general trend that any anatomical direction was greater than the other two directions. This goes against theory that the AP move is generally larger4. Out of all of the studies, only 22% of the mean set-up errors were more than 3mm, which is usually allowed for with the CTV-PTV expansion margin. However as 100% of the set-up errors were not less than 3mm, this highlights the importance of using IGRT to ensure precise radiotherapy. The primary goal of EBRT is tumour control, which can be measured using disease free survival. In one key study comparing patients with rectal/bladder preparation and those without, the percentage survival was higher in the rectal/bladder preparation group for both 5 and 10 year follow up5. Conclusion Bowel/bladder preparation can be useful in stabilising key organs in the region of the prostate; important in replicating internal anatomy from planning CT to treatment. This review showed that preparations are very varied and although useful at replicating OAR volumes, don’t necessarily always successfully stabilise the geographical location of the prostate. However, the most appropriate method could not be definitively determined and further studies are needed. References 1. Cancer Research UK. Prostate cancer statistics. 2017. http://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/prostate-cancer (accessed 12 December 2020). 2. Zelefsky MJ, Deasy JO. Improved long-term outcomes with IMRT: is it better technology or better physics? Int J Radiat Oncol Biol Phys. 2013;87(5):867-8. 3. Seo YE, Kim TH, Lee KS, Cho WY, Lee HS, Hur WJ, Choi Y. Interfraction prostate movement in bone alignment after rectal enema for radiotherapy. Korean J Urol. 2014 Jan;55(1):23-8. Doi: 10.4111/kju.2014.55.1.23 4. Gurjar OP, Arya R, Goyal H. A study on prostate movement and dosimetric variation because of bladder and rectum volumes changes during the course of image-guided radiotherapy in prostate cancer. Prostate Int. 2020;8(2):91-97. Doi: 10.1016/j.prnil.2019.12.003 5. Maggio A, Gabriele D, Garibaldi E, Bresciani S, Delmastro E, Di Dia A, Miranti A, Poli M, Varetto T, Stasi M, Gabriele P. Impact of a rectal and bladder preparation protocol on prostate cancer outcome in patients treated with external beam radiotherapy. Strahlenther Onkol. 2017 Sep;193(9):722-732. Doi: 10.1007/s00066-017-1163-4

Item Type:	Poster
Divisions:	Faculty of Health and Life Sciences Faculty of Health and Life Sciences > Institute of Population Health Faculty of Health and Life Sciences > Institute of Population Health > School of Health Sciences
Depositing User:	Symplectic Admin
Date Deposited:	21 Apr 2022 07:47
Last Modified:	18 Jan 2023 21:04
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3153529