# Seven-Year PSA ≤ 0.2 ng/mL After High-Dose-Rate Brachytherapy Indicates Eligibility for Discontinuing PSA Surveillance in Prostate Cancer

## TL;DR

This study shows that prostate cancer patients with a PSA level of 0.2 ng/mL or lower seven years after HDR-BT treatment likely do not need further PSA monitoring.

## Contribution

The study identifies a specific PSA threshold and timing for safely stopping surveillance after HDR-BT treatment.

## Key findings

- PSA levels at 5 and 7 years post-treatment were significantly linked to oncological outcomes.
- No recurrences were observed in patients with PSA ≤0.2 ng/mL at 7 years.
- A PSA >0.2 ng/mL at 5 years was a strong predictor of recurrence.

## Abstract

Although both domestic and international guidelines provide recommendations for follow-up methods after definitive treatment of prostate cancer, they do not clearly specify when follow-up can be safely discontinued. This retrospective study aimed to determine the optimal timing for cessation of monitoring following high-dose-rate brachytherapy. Findings showed that prostate-specific antigen (PSA) levels at 5 and 7 years post-treatment were significantly associated with oncological outcomes. Notably, no recurrences were observed among patients whose PSA levels remained ≤0.2 ng/mL at 7 years post-treatment. These findings suggest that PSA surveillance may be safely discontinued at 7 years in this population, providing a clear, evidence-based benchmark for ending long-term monitoring. This could reduce patient burden and healthcare costs without compromising safety.

Background: We evaluated the long-term treatment outcomes of patients with clinically localized and locally advanced prostate cancer (PC) who underwent high-dose-rate brachytherapy (HDR-BT) combined with external beam radiotherapy (EBRT). The primary objective was to identify the optimal timing for discontinuing prostate-specific antigen (PSA) monitoring after HDR-BT. Methods: This analysis included 338 patients with PC who received HDR-BT combined with EBRT between 2006 and 2022 and had a minimum follow-up of 5 years. The patients were stratified based on their PSA levels, and factors associated with recurrence were identified. Results: The median observation period was 8.9 years (range, 5.0–19.0 years). The 10-year recurrence-free survival rate was 92.0%, with 26 recurrences. PSA levels at 5 and 7 years were significantly correlated with oncological outcomes after HDR-BT. Multivariate analysis revealed that a PSA level of >0.2 ng/mL at 5 years was an independent poor prognostic factor for recurrence (hazard ratio, 117.57; 95% confidence interval, 6.22–2223.37; p = 0.001). No patient with a PSA level of ≤0.2 ng/mL at 7 years developed recurrences. Conclusions: Based on our long-term data, we propose that PSA monitoring may be safely discontinued in patients with a PSA level of ≤0.2 ng/mL 7 years after HDR-BT because the risk of recurrence beyond this point is exceedingly low.