Predictors and rate of adjuvant radiation therapy following radical prostatectomy: a report from the Prostate Cancer Registry

Abstract

INTRODUCTION: Long-term data from three randomized trials have demonstrated that adjuvant radiation therapy (ART) reduces the rate of biochemical failure in high-risk men following radical prostatectomy (RP). One of these trials has shown a survival advantage. We investigated the rate of ART in Victoria and the predictors for this treatment. METHODS: We analysed data from eligible patients who were notified to the Victorian Prostate Cancer Registry (PCR) by 37 Victorian hospitals between 1 August 2008 and 31 October 2011. We defined ART as radiation therapy (RT) delivered within 6 months of RP. Predictors of ART receipt were modelled using adjusted and unadjusted logistic regression. RESULTS: There were 4626 eligible cases from which 2018 underwent RP with recorded date of surgery. Of these eligible prostatectomy cases, a total of 89 received ART. A subgroup of 833 men had an adverse pathologic feature, of whom 78 received ART. In a multivariate model, pathologic tumour stage pT3a (odds ratio (OR) 2.64; 95% confidence interval (CI) 1.4-5.00; P = 0.003), pT3b (OR 4.58; 95% CI 2.12-9.89; P = 0.000), a positive surgical margin (OR 8.91; 95% CI 4.61-17.2; P = 0.000) and pathologic Gleason grade >7 (OR 7.18; 95% CI 1.54-33.6; P = 0.012) predicted receipt of ART. CONCLUSION: Adverse pathologic features and high pathologic Gleason score predict for receiving ART in Victorian men after RP, but overall, ART is not commonly prescribed. This finding is consistent with other published series and may reflect clinician scepticism regarding the benefit of ART over salvage RT and concern about toxicity and the risk of over treatment.