ASTRO 2020: Long-Term Follow-up With Low–Dose-Rate Prostate Brachytherapy
Posted: Friday, November 20, 2020
Retrospective reporting has limited the use of low–dose-rate prostate brachytherapy for prostate cancer local recurrence after external-beam radiotherapy. During the virtual edition of the 2020 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 4), Juanita Mary Crook, MD, of the British Columbia Cancer Agency, and colleagues reported their 5-year follow-up on efficacy outcomes from their phase II NRG/RTOG-0526 trial.
“This is the first prospective multicenter trial to report outcomes of salvage low–dose-rate brachytherapy for local tumor progression after external-beam radiotherapy,” stated the investigators. “We previously reported late grade 3 gastrointestinal and genitourinary adverse events occurring in 14%. We now report 5-year freedom from biochemical failure at 68%, comparable to other salvage modalities.”
Patients in this study had intermediate- or low-risk prostate cancer and were treated with external beam radiotherapy; they had a local recurrence more than 30 months after treatment. Of 100 eligible participants, 92 were analyzable, and each received either 140 Gy with iodine-125 or 120 Gy with palladium-103. All patients were analyzed for secondary clinical outcomes and were followed for 5 to 10 years after salvage brachytherapy.
Androgen deprivation was combined with salvage brachytherapy in 16%, and the median period from initial external-beam radiotherapy was 85 months. Disease-free survival at 5 years was 61%, but it dropped to 33% at 10 years. The 10-year overall survival, local failure, and freedom from biochemical failure rates were 70%, 5%, and 54%, respectively. A total of 19 patients died during the study: 4 had local recurrence, and 14 had distant disease failure.
Disclosure: For full disclosures of the study authors, visit redjournal.org.