Session Item

Prostate cancer clinical guidelines are created by experts in each field, based on evidence, reality and clinical conditions in each region and/or country. However, there are discrepancies between these guidelines, namely risk stratification, which play a key role in the clinical practice. This retrospective study reviews the outcome of patients treated with monotherapy iodine-125 brachytherapy treatment (I-125 BT) with low and intermediate-risk prostate cancer, stratified by the by NCCN and EAU - EANM - ESTRO - ESUR - ISUP – SIOG (EAU) patient selection criteria, and analyze whether there is a correlation between different guideline selection criteria and treatment outcome.

This study included 250 patients with biopsy confirmed prostate cancer, treated with I 125 BT in a single tertiary center, between January 2013 and October 2016. The analysis was based on the definition of biochemical recurrence according to the Phoenix Consensus, and focused on the clinical baseline characteristics, relapse-free survival (RFS), disease-specific survival (DSS), and overall survival (OS). The impact of stratification based in NCCN or EAU guidelines on RFS, DSS and OS was assessed using log rank test for univariate analysis and the Cox regression for multivariate analysis. Statistical analysis was performed with SPSSv27.

Median follow-up period was 79 months (39 – 105 months). One hundred and seventy - seven low risk and sixty - five  favorable intermediate risk patients  were eligible to BT according NCNN, and fifteen low risk and twenty-five intermediate risk were identified as disapproving as per to EAU. Eight patients were disapproving as per NCCN (unfavorable intermediate risk), but were eligible according to EAU guidelines. Five-year OS, RFS, and DSS were 98.8%, 94.4%, and 100%, respectively. In univariate analysis, the percentage of positive cores on prostate biopsies did not add clinically significant information regarding time to PSA failure after I-125 BT (p=0.793). There was also no relation between disapproving as per EAU guidelines and RFS or DSS (p=0.387; p=0.668 respectively). In Cox multivariate analysis, disapproving as per EAU guidelines was associated with decreased RFS (p=0.014). 

This study demonstrated excellent survival rates, RFS, and DSS of monotherapy iodine-125 brachytherapy and that is an effective treatment for selected cases. Patients who were not eligible according to EAU guidelines demonstrated a lower RFS in Cox multivariate analysis. However, due to the retrospective design of this study, no definite conclusions can be drawn, and future studies are needed to safely assess a possible relationship between these factors. Investigations of such relationships may result in a common criterion that includes all affected men in our societies and more rational treatment of Prostate Cancer.