Presentation Authors: Kenan Celtik*, Houston, TX, Christopher Wallis, Toronto, Canada, Mary Lo, Ann Hamilton, Los Angeles, CA, Steven Fleming, Lexington, KY, Xiao-Cheng Wu, New Orleans, LA, Roger Anderson, Charlottesville, VA, Brian Miles, Raj Satkunasivam, Houston, TX
Introduction: Comparative effectiveness of RP and IMRT for PCa have been poorly studied, and limited by poor measurement of patient comorbidities. We sought to examine survival differences using a population-based cohort with robust data on comorbidities.
Methods: The CDC POC-BP study was conducted between 2007-2009 and involved medical record abstraction of 8229 cases of localized PCa diagnosed in 2004 across the CDC National Program of Cancer Registries. We identified 3019 RP and 667 IMRT patients. Propensity score matching (PSM) was used to balance socio-demographic and clinical characteristics, including comorbidities assessed by the Adult Comorbidity Evaluation-27 (ACE-27) score, between patients receiving RP and IMRT. We compared overall survival (OS) and prostate cancer specific survival (CSS) between RP and IMRT using Kaplan Meier curves and Cox proportional hazard analyses. We performed a pre-specified subgroup analysis in patients with National Comprehensive Cancer Network (NCCN) high risk, localized PCa treated with RP (n=89) and IMRT (n=95).
Results: PSM was used to identify 502 RP and 502 IMRT patients that were well balanced with respect to standardized differences. Median follow-up was 10.1 years (IQR 6.9-10.8). Nine-year OS was 77.3% (95% CI 73.5%-81.1%) and 72.4% (95% CI 68.3%-76.4%) for RP and IMRT, respectively (Figure 1). IMRT as compared to RP was associated with a 29% increase in the risk of overall mortality [HR 1.29 (95% CI 1.02-1.65]. There was no significant difference in CSS between IMRT and RP [HR 1.70 (95% CI 0.77-3.78)]. In the subset of patients with NCCN high risk PCa, IMRT as compared to RP was not associated with a statistically significant difference in OS [HR 1.40 (95% CI 0.86-2.29) or CSS [HR 1.71 (95% CI 0.56-5.25)].
Conclusions: In this population-based cohort study examining contemporary localized prostate cancer treatments, we found an increased risk of all-cause, but not prostate cancer specific mortality associated with IMRT as compared to RP. Limitations inherent in observational studies including residual confounding should be considered in the interpretation of this data.
Source of Funding: The Hamill Foundation. The Breast and Prostate Cancer Data Quality and Patterns of Care Study was supported by the Centers for Disease Control and Prevention through cooperative agreements with the California Cancer Registry (Public Health Institute) (1-