PO51 Presentation Time: 10:00 AM: Permanent I-125 Seeds Prostate Cancer Mono-Brachytherapy: Outcomes in 273 Patients

Abstract

<h3>Purpose</h3> Report outcomes of patients undergoing I-125 seeds permanent low-dose-rate (LDR) mono-brachytherapy (mBT) in terms of OS, biochemical failure-free survival (BFFS), recurrence-free survival (RFS) and GU-GI toxicities in localized prostate cancer (LPC). <h3>Materials and Methods</h3> Between 2001 and 2015, 273 patients, undergoing I-125 LDR mBT with no prior curable treatment, with a prostate volume (pV) ≤50cc, cT1 à cT2c (NCCN classification) et iPSA ≤ 20 ng/ml were included and examined. <h3>Results</h3> With a median followup of 68 months, a biochemical failure occurred in 8 patients (4%) patients. The 5 and 8y-BFFS, defined by the Phoenix criterion, were 98.2% and 88.9%, worse for intermediate risk (IR) as compared with low risk (LR), with a 8y-BFFS of 85.7% and 91.5% respectively (p-value=0.01). The 8y-RFS were 96% and 90% for LR and IR respectively. The only factor statistically significant on OS was the age ≤ 65y with a 5 and 8y-OS of 93%/83% vs 89%/73% for ≤ 65y or >65y patients (p-value: 0.031). Surprisingly, we found in a sub-group analysis that 8y-OS for Gleason score 7 disease (GS 4+3 or 3+4) was higher than ≤ Gleason score 6 (83% vs 62%). No difference in outcomes between IR vs LR and ≤ 65y vs >65y patients was observed in terms of 8y-distant metastasis-free survival (DMFS) and prostate cancer specific survival (pCSS). The toxicity profiles suggested, from a follow-up of at least 2 years, that ≥ G3 urinary, GI and sexual toxicities were 5.5%,0.7%, 0% respectively. <h3>Conclusion</h3> I-125 permanent seeds LDR mBT provided excellent outcomes in this study. 8y-local recurrence was 6.5%. Therefore, LDR brachytherapy can be considered and still proposed as an effective treatment option for IR and LR LPC patients.