Randomized Trial Supports Dose-De-Escalated Pd-103 LDR Brachytherapy for Low-Risk Prostate Cancer

A recently published randomized clinical trial by King et al. confirms that dose-de-escalated Palladium-103 (Pd-103) LDR brachytherapy (110 Gy) provides excellent long-term cancer control with low toxicity for patients with low-risk prostate cancer. At a median follow-up of more than 10 years, biochemical failure rates remained below 3% in both the standard-dose (125 Gy) and de-escalated treatment arms, with no significant differences in Grade 3 genitourinary toxicity, supporting dose-de-escalated Pd-103 as a safe and effective treatment strategy.

The authors highlight several reasons why Pd-103 may be particularly well suited for evaluating dose de-escalation:

1. shorter half-life and resultant higher-dose-rate may have favorable radiobiological properties, particularly for prostate cancer tumors with lower α/β ratios;
2. greater dosimetric heterogeneity, allowing higher intraprostatic dose intensity despite a lower prescription dose; and
3. evidence suggesting improved oncologic outcomes compared with I-125 in longer-term, multi-institutional analyses. Additional studies also suggest dose-de-escalated Pd-103 may reduce acute urinary toxicity.

The study acknowledges that since the trial’s initiation in 2005, active surveillance has become the predominant strategy for low-risk prostate cancer. However, for patients who elect treatment due to higher-volume disease, concerning MRI findings, genomic risk factors, or family history, dose-de-escalated Pd-103 brachytherapy offers a well-supported treatment option.