Both comorbidity and worse performance status are associated with poorer overall survival after external beam radiotherapy for prostate cancer

Abstract

Background: In this retrospective study, we evaluated the biochemical recurrence rate, metastatic disease progression, and prostate cancer-specific and overall survival in patients curatively treated with external beam radiotherapy (EBRT) for early prostate cancer (PC). We also examined the prognostic effect of comorbidity by Charlson Comorbidity Index (CCI) and overall performance status by Eastern Clinical Oncology Group (ECOG) score. Methods: A total of 665 men treated between 2008 and 2013 were enrolled from Tampere University Hospital, Finland. Prostate-specific antigen (PSA) tests and hospital records were used to determine the 5-year survival for each aforementioned endpoint using a Kaplan-Meyer estimate. To analyze the impact of the selected prognostic factor, we used a Cox regression model to calculate the corresponding hazard ratio (HR) and 95% confidence interval (CI). Results: With a median follow-up-time of 7.12 years, the 5-year overall survival (OS) after EBRT was 88.9% [86.5-91.3%], prostate cancer-specific survival (PCSS) was 97.9% [96.7-99.1%], metastasis-free survival (MFS) 94.8% [93.0-96.6%] and biochemical recurrence-free survival (BRFS) 88.7% [86.2-91.2%]. Both CCI (HR = 1.38, [1.25-1.51]) and ECOG score (HR = 1.63, [1.29-2.05]) declined OS, as well as Gleason score and T score (P < 0.05). Gleason score and T grade also associated to worse PCSS, MFS and BRFS. Conclusions: CCI and ECOG score are useful tools in evaluating the overall life expectancy of the patient after EBRT for PC. T-stage and Gleason score remain still the major prognostic factors.