Is there a role for endorectal balloons in prostate radiotherapy? A systematic review

Background and purpose: Endorectal balloons (ERBs) are being used in prostate radiotherapy for prostate immobilization and rectal wall (Rwall) sparing. Some of their aspects, however, have been questioned, like patient's tolerance and their value in modern high-precision radiotherapy. This paper gives an overview of published data concerning ERB application in prostate radiotherapy. Materials and methods: Systematic literature review based on PubMed/MEDLINE database searches. Results: Overall, ERBs are tolerated well, although patients with pre-existing anorectal disease have an increased risk of developing ERB-related toxicity. Planning studies show reduced Rwall and anal wall (Awall) doses with ERB application. Clinical data, however, are scarce, as only one study shows reduced late rectal damage. There is no consensus about the immobilizing properties of ERBs and it is recommended to use additional set-up and correction protocols, especially because there are potential pitfalls. Conclusion: ERBs seem well-tolerated and in planning studies reduce anorectal wall doses. This may lead to reduced anorectal toxicity, although clinical studies are warranted to confirm this hypothesis and to further investigate the immobilizing properties of ERBs, preferably in combination with advanced techniques for position verification.