RECTAL SPACERS achieved comparable prostate to rectum separation and demonstrated an acceptable short-term safety profile in patients with cT3 prostate cancer undergoing external beam radiotherapy, according to findings from a prospective cohort study.
Biodegradable rectal spacers are widely used in localised prostate cancer to increase the distance between the prostate and rectum, thereby reducing unintended rectal irradiation. However, evidence in locally advanced disease has remained limited.
To address this gap, researchers conducted a prospective single centre study between 2022 and 2024 involving 181 men with biopsy confirmed cT1 to cT3 prostate cancer scheduled for external beam radiotherapy.
All participants underwent insertion of either a polyethylene glycol hydrogel spacer or a hyaluronic acid spacer before treatment.
Among the cohort, 62 patients had cT3 disease and 119 had cT1c or cT2 disease. Post-insertion rectal spacing was largely comparable between groups.
At the mid-gland, spacing measured 1.00 cm±0.36 in the cT3 group versus 1.05 cm±0.37 in the cT1c/cT2. At the apex, measurements were 0.52 cm±0.27 and 0.59 cm±0.30, respectively. A significantly greater separation at the base was observed in the cT3 cohort (0.94 cm±0.32 versus 0.82 cm±0.30).
Researchers reported no significant differences in gastrointestinal toxicity between disease stages.
Acute grade 1 or 2 gastrointestinal toxicity occurred in 12.9% of patients with cT3 disease compared with 5.0% of patients with cT1c/cT2 disease.
Late toxicity rates were 4.3% and 1.1%, respectively. Importantly, no grade 3 or higher toxicity was recorded in either group. Procedure related complications were similarly low.
Temporary urinary retention requiring catheterisation occurred in 17.7% of patients with cT3 disease and 13.4% of those with cT1c/cT2 disease.
No patients experienced refractory urinary retention, infective complications, or rectal mucosal injury.
Notably, patients with cT3 disease were more likely to receive higher dose radiotherapy regimens, yet toxicity outcomes remained comparable.
Researchers suggested this may indicate that rectal spacers retain their protective effect across varying treatment intensities and disease stages.
Early oncological outcomes were also reassuring. Freedom from biochemical failure was 98.1% in the cT3 group and 100% in the cT1c/cT2 group during a median follow-up of 8 months.
The researchers emphasised that longer follow up will be required to assess long term cancer control and late toxicity outcomes.
Overall, the findings suggest that rectal spacers could play an increasingly important role in supporting safer, more precise external beam radiotherapy for patients with locally advanced prostate cancer as longer-term evidence continues to emerge.
Reference
Wang K et al. Safety and efficacy of rectal spacers in locally advanced prostate cancer. Sci Rep. 2026;DOI:10.1038/s41598-026-66499-w
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