Introduction

1. No. 029 Early Biochemical Recurrence Following Radical Prostatectomy Does Not Increase Mortality in Men with Low Risk Prostate Cancer Anthony TA1,2, Gianluca SEVERI2,3, David MULLER2,3, Helen KELSALL4, Jeremy L MILLAR4,5, Rodney SYME6, John PEDERSEN7, Graham G GILES2,3, Damien BOLTON1,2 1The Austin Hospital, 2The University of Melbourne, 3The Cancer Council of Victoria, 4Monash University, 5The Alfred Hospital, 6Epworth Freemasons Hospital, 7TissuPath Introduction Early biochemical recurrence (BCR) following radical prostatectomy is an adverse prognosticator of prostate cancer-specific mortality (PCM).1 Data evaluating the temporal relationship between BCR and survival is lacking from population-based studies. The Victorian Radical Prostatectomy Register (VRPR) represents a whole-of-population series of screened men who underwent radical prostatectomy between 1995 and 2000. Results Of 2154 eligible patients, follow-up PSA data was available for 2116 men. Median age at surgery was 62 years. Median length of post-surgery follow-up was 10.3 years, during which 81 men (3.8%) died from prostate cancer. Median length of follow-up from time of BCR was 7.5 years. Overall, 695 men (32.8%) experienced BCR, of which 82% occurred within 5 years, 16% between 5 and 10 years, and 2% more than 10 years post-surgery. 66 men (9.5%) who experienced BCR died from prostate cancer. There were no significant differences in age or surgical margin positivity between men who died following BCR than those who did not, although they were more likely to have higher Gleason score and tumour stage compared to men surviving with prostate cancer recurrence. The Poisson model evaluating the relationship between interval to BCR and PCM is shown in Figure 1. The time interval between surgery and BCR was a strong correlate of PCM for men with high risk features of prostate cancer. Men with combined higher risk Gleason score >7 (with primary Gleason 4 or greater) and extraprostatic disease (>pT3a) had significant risk of death with early recurrence. For these men, early BCR at 2 years post-surgery was associated with a predicted PCM rate of 0.50 (95% CI 0.33-0.67) per 10-person years. This risk reduced to 0.14 (95% CI 0.00-0.28) if BCR occurred at 5 years post-surgery, but remained substantial. Conversely, men with both lower risk Gleason score < 7 (primary Gleason 3 or less) and organ-confined disease (<pT2c) had low mortality regardless of early or delayed BCR. The predicted PCM rate for these men was 0.04 if BCR occurred at both 2 years (95% CI 0.02-0.06) and 5 years (95% CI 0.00-0.08). Men with intermediate risk prostate cancer, having only one of the above high risk features, had higher predicted PCM with early BCR; however, their risk is comparable to men with low risk prostate cancer if they experienced delayed BCR. Aim To describe clinical and tumour characteristics of men who experienced BCR following radical prostatectomy To evaluate the relationship between interval to BCR and PCM Methods Study Sample The VRPR was approved by the ethics committee of The Cancer Council of Victoria. Eligible subjects were identified via histopathology reports of prostate cancer submitted to the Victorian Cancer Registry (VCR), a state-wide register which receives mandatory reports of all new cancer diagnoses. Men who underwent radical prostatectomy between 1 July 2005 and 31 December 2000 were eligible. Tumour characteristics of prostatectomy specimens were obtained via record linkage to the VCR. Follow-up PSA follow-up was obtained via record linkage to pathology laboratories and assistance of treating urologists. BCR was defined as two consecutive PSA values >0.2µg/L. Follow-up ended at either date of death or 1 January 2009. Deaths were identified via record linkage to the Victorian Register of Births, Deaths and Marriages. Statistical Analysis Poisson regression models were fit to the data with PCM as the outcome. Mortality rates were expressed as deaths per 10 person-years. Time from surgery to BCR was modelled as a continuous covariate. Predicted marginal mortality rates were calculated from the fitted models for given values of time to BCR. Models included age at surgery and categorised Gleason score and tumour stage. Statistical analyses were performed using Stata 12.0 (Stata corporation, College Station, TX, USA) Low risk Intermed. risk High risk Mortality Rate per 10-person Years Time from Radical Prostatectomy to Biochemical Recurrence Figure 1.Predicted Prostate Cancer-Specific Mortality Low risk: < pT2c and Gleason score < 3+4 Intermediate risk: < pT2c and Gleason score > 4+3, or pT3a/3b and Gleason score < 3+ 4 High risk: > pT3a and Gleason > 4+3 Conclusions Findings from this whole-of-population radical prostatectomy registry confirm that men with favourable tumour characteristics at the time of surgery are at low risk of dying from prostate cancer. Their risk remains low even if they experience early biochemical recurrence. In the event of cancer recurrence, this sub-group may be counselled regarding their favourable long-term prognosis. References 1. Freedland SJ, Humphreys EB, Mangold LA, Eisenberger M, Partin AW. Time to prostate specific antigen recurrence after radical prostatectomy and risk of prostate cancer specific mortality. Journal of Urology 2006;176:1404-8. Acknowledgements Participating urologists The Cancer Council of Victoria, Melbourne, Australia The Whitten Foundation Poster presentation sponsor