The evolving landscape of practice pattern and survival outcomes in the management of localized low-risk prostate cancer.

e17057 Background: The majority of patients with low-risk prostate cancer (LRPC) are candidates for active surveillance (AS) or definitive local treatment, which may include radical prostatectomy (RP), external beam radiotherapy (EBRT), or prostate seed implant (PSI). In the recent edition of the National Comprehensive Cancer Network (NCCN) guidelines, the “preferred” status was removed for AS, which rekindled a debate and interest in the management of LRPC. In this study, we analyzed the treatment pattern and impact of various treatment modalities on the survival of patients with LRPC using a large patient population provided by the National Cancer DataBase (NCDB). Methods: Patients with LRPC, as defined by the NCCN criteria, between 2004 and 2015 from NCDB were analyzed. Patients are categorized by treatment modalities, including RP, EBRT, PSI, and those who received no local therapy (NLT). Only patients with low Charlson-Deyo comorbidity score, 0 or 1 were included to ensure comparability between treatment groups. A multivariable Cox regression model was developed to determine the adjusted odds of patients' survival. The Kaplan Meier survival plots stratified by treatment were generated to establish the median overall survival (OS). The log-rank test was used to determine significance between treatment groups. Cox regression models were used to produce parameter estimates and hazard ratio (HR) for each age group. Results: A total of 195,452 patients with LRPC were identified from 2004 to 2015. There was a significant practice pattern change with increased utilization of NLT over time, from 11.3% in 2004 to 53.5% in 2015, with a turning point in 2009. The utilization was peaked for RP at 41.6% in 2008, EBRT at 24.3% in 2006, and PSI at 35.3% in 2004, but dropped to 17.6%, 18.1%, and 10.8%, respectively, in 2015. Of different treatment modalities, compared to NLT, RP provided a superior OS with a HR of 0.662, p < .0001; PSI also improved OS with an HR of 0.795, p < .0001. However, EBRT did not improve OS and was potentially detrimental, HR = 1.049, p = 0.01. With age-matched subgroup analysis, the survival advantage based on HR of RP relative to NLT favors RP until the age of 74 but diminishes as age increases. In patients younger than 70, NLT provided comparable survival to EBRT or PSI. The survival advantage of EBRT or PSI is only seen in older patients, at age of 75 or older for EBRT and 70 or older for PSI. Conclusions: There has been a significant treatment pattern change between 2004 and 2015. AS, as represented by the NLT in this study, has become the dominant choice of treatment for LRPC. However, of different treatment modalities, both RP and PSI improve OS. The patients managed with AS had comparable OS to those who received EBRT. The survival benefit of RP is mostly seen in younger patients. Only older patients benefit from PSI or EBRT. This study is limited by its retrospective nature and inherent bias in NCDB.