# Functional outcomes and toxicity following focal low‐dose‐rate brachytherapy for low–intermediate risk prostate cancer

## TL;DR

This study evaluates the effects of focal low-dose-rate brachytherapy on prostate cancer patients, finding minimal long-term side effects and good functional outcomes.

## Contribution

The study provides new evidence on the functional outcomes and toxicity of focal low-dose-rate brachytherapy for prostate cancer.

## Key findings

- Focal LDR brachytherapy showed minimal long-term toxicity with no Grade ≥3 adverse events.
- Erectile function declined temporarily but remained within minimal important difference thresholds for most patients.
- Bowel function was largely preserved, with no significant changes in EPIC scores.

## Abstract

We aim to prospectively evaluate functional outcomes and toxicity following focal low‐dose‐rate (LDR) brachytherapy for low–intermediate risk prostate cancer (PCa).

LIBERATE is a clinical registry of men treated with focal LDR brachytherapy for low–intermediate risk PCa since September 2019. Follow‐up occurred at 6 weeks and every 3 months thereafter. Outcomes were assessed using validated patient‐reported outcome measures (PROMs): IPSS, Expanded PCa Index Composite (EPIC) Bowel Assessment, and International Index of Erectile Function (IIEF‐5). Adverse events (AEs) were clinically graded per Common Terminology Criteria for Adverse Events v5.0. Minimal important differences (MIDs) were defined as ±3.1 for IPSS, ±5 for EPIC bowel domain, and ±4 for IIEF‐5.

Of 120 patients enrolled, 88/120 (73.3%) had ≥12 months follow‐up, and 79/88 (89.7%) completed PROMs with a median (IQR) follow‐up of 33 (26–41) months. At 6 weeks, a transient, statistically and clinically significant increase in IPSS was observed, which returned to baseline by 12 months (median IPSS: 6 at baseline, 12 at 6 weeks, 6 at 12 months). EPIC bowel scores showed no significant changes, with 72 (91.1%) patients having rectal spacer. Among 66 sexually active men, 40 (60.6%) had no or mild erectile dysfunction (ED) at baseline, with a median IIEF‐5 score of 22.5, decreasing to 22 at 6 weeks and plateauing at 21 at 6 months, none meeting MID criteria. For the 26 patients with mild to severe ED at baseline, the median IIEF‐5 score declined from 10 at baseline to 5 at 6 months, with partial recovery followed by a drop to 5.5 at 2.5 and 3 years. Declines at 6 months and beyond 2 years were both statistically and clinically significant. No Grade ≥3 AEs were reported.

Focal LDR brachytherapy is associated with favorable functional outcomes and minimal toxicity. Further studies are required to evaluate long‐term results.