Clinical utility of endorectal balloons in prostate cancer external beam radiotherapy: a systematic review and meta-analysis.

PURPOSE: This study aimed to systematically evaluate the clinical utility of endorectal balloons (ERB) for motion management and organ-at-risk sparing in prostate cancer patients receiving external beam radiotherapy (EBRT) or stereotactic body radiotherapy (SBRT).

MATERIALS AND

METHODS

A systematic search was conducted in Ovid MEDLINE, Embase, the Cochrane Library, and Korean databases through May 8, 2024. Primary outcomes included safety, toxicity, prostate motion, and dosimetric parameters. The risk of bias was assessed using the Risk of Bias Assessment tool for Non-randomized Studies 2.0 tools. Meta-analysis was conducted using Review Manager 5.3.

RESULTS

Twenty-seven studies (3 prospective cohort studies, 24 retrospective studies) were included, covering 22 EBRT and 5 SBRT cohorts. Reported adverse events were mild and transient. One prospective study demonstrated a significant reduction in grade 1 late rectal toxicity (p = 0.003). ERB use significantly stabilized the prostate, reducing both intra- and interfractional motion, particularly minimizing displacements >5 mm. Meta-analysis revealed that ERB significantly lowered the mean radiation dose to the rectum (mean difference [MD], -3.40 Gy; 95% confidence interval [CI], -6.70 to -0.10) and anal wall (MD, -6.06 Gy; 95% CI, -9.78 to -2.35) in EBRT. Similarly, in SBRT, ERB was associated with reduced rectal wall dose (MD, -2.63 Gy; 95% CI, -4.49 to -0.77).

CONCLUSION

ERB appears to be a relatively safe and clinically useful adjunct for enhancing treatment precision in prostate cancer radiotherapy. By stabilizing prostate motion and reducing radiation exposure to the rectum and anal wall, ERB optimizes the therapeutic ratio.