Low dose rate brachytherapy (LDR-BT) as monotherapy for early stage prostate cancer in Italy: Practice and outcome analysis in a series of 2237 patients from 11 institutions

Objective: Low-dose-rate brachytherapy (LDR-BT) in localized prostate cancer is available since 15 years in Italy. We realized the first national multicentre and multidisciplinary data collection to evaluate LDR-BT practice, given as monotherapy, and outcome in terms of biochemical failure. Methods: Between May 1998 and December 2011, 2237 patients with early-stage prostate cancer from 11 Italian community andacademic hospitals were treated with iodine- 125 (¹²⁵I) or palladium-103 LDR-BT as monotherapy and followed up for at least 2 years. ¹²⁵I seeds were implanted in 97.7% of the patients: the mean dose received by 90% of target volume was 145Gy; the mean target volume receiving 100% of prescribed dose (V₁₀₀) was 91.1%. Biochemical failurefree survival (BFFS), disease-specific survival (DSS) and overall survival (OS) were estimated using Kaplan-Meier method. Log-rank test and multivariable Cox regression were used to evaluate the relationship of covariates with outcomes. Results: Median follow-up time was 65 months. 5- and 7-year DSS, OS and BFFS were 99 and 98%, 94 and 89%, and 92 and 88%, respectively. At multivariate analysis, the National Comprehensive Cancer Network score (p<0.0001) and V₁₀₀ (p=0.09) were correlated with BFFS, with V₁₀₀ effect significantly different between patients at low risk and those at intermediate/high risk (p=0.04). Short follow-up and lack of toxicity data represent the main limitations for a global evaluation of LDR-BT. Conclusion: This first multicentre Italian report confirms LDR-BT as an excellent curative modality for low-/intermediate-risk prostate cancer. Advances in knowledge: Multidisciplinary teams may help to select adequately patients to be treated with brachytherapy, with a direct impact on the implant quality and, possibly, on outcome.