850 POSTER The new RTOG-ASTRO biochemical relapse definition is a more appropriate endpoint for multivariate analysis of prostate cancer outcomes

4619 Background: PSA velocity has recently been reported as a significant predictor of prostate cancer-specific mortality in early-staged cancer patients selected from a large screening trial where the median PSA was 4.3ng/ml. In order to determine the broad applicability of these data to a more general population, we examined the effect of PSAV in a referral cohort. Methods: We analyzed over 643 prostate cancer cases diagnosed from 1995–2005. 196 patients underwent RP as definitive therapy. One patient received neoadjuvant hormonal therapy and was excluded. Our goal was to identify whether PSAV prior to RP was predictive of Relapse-Free Survival (RFS) and Overall Survival (OS). 156 patients had at least 2 pre-op PSA values available for the calculation of PSAV (median = 3 values/patient). PSAV was calculated by linear regression analysis using all pre-treatment PSA values available. Results: With a median f/u of 54 months, there were 14 deaths and 26 patients had biochemical relapse. At 5 years, OS was 93% and RFS was 91%. Surprisingly, no patients with biochemical relapse have died, and thus prostate cancer-specific mortality is 0%. In addition to the variables in the table below, seminal vesicle involvement (p = 0.015) and margin positivity (p=0.005) were also significantly associated with RFS confirming the expected prognostic factors in our cohort. On multivariate analysis, Gleason Grade was the only significant predictor of overall survival. For RFS, Gleason Grade, margin involvement, and pre-treatment PSAs were the only significant variables. Neither PSAV nor PSA Doubling Time were significantly associated with RFS or OS by univariate or multivariate analysis. Conclusions: Pre-treatment PSAV is not significantly associated with prostate cancer outcomes in a heterogenous population referred for an elevated PSA. Gleason Grade is still the most significant predictor of overall survival. [Table: see text] No significant financial relationships to disclose.

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Long-term efficacy of stereotactic body radiotherapy for localized prostate cancer: A multi-institutional pooled analysis.

Journal of Clinical Oncology ◽

10.1200/jco.2013.31.6_suppl.9 ◽

2013 ◽

Vol 31 (6_suppl) ◽

pp. 9-9 ◽

Cited By ~ 1

Author(s):

Patrick Kupelian ◽

Alan J. Katz ◽

Debra Freeman ◽

Irving D. Kaplan ◽

Donald B. Fuller ◽

...

Keyword(s):

Prostate Cancer ◽

Multivariate Analysis ◽

High Risk ◽

Cancer Patients ◽

Gleason Score ◽

Stereotactic Body Radiotherapy ◽

Androgen Deprivation ◽

Localized Prostate Cancer ◽

Biochemical Relapse

9 Background: The purpose of this study is to report biochemical relapse-free survival (bRFS) rates for a group of localized prostate cancer patients from a pooled multi-institutional dataset with at least 5 years follow-up after stereotactic body radiotherapy (SBRT). Methods: The outcome data from 1101 patients treated with SBRT between 2003 and 2011 were pooled from 8 institutions. A subset of 135 cases had a minimum 5 years follow-up. All 135 cases had clinical stage T1 or T2A disease. The distribution by Gleason score (GS) was <6 in 80% and 7 in 20%. The median pretreatment PSA (iPSA) level was 5.1 ng/ml (range: 0.1-27.8). The distribution by risk was 77% low, 21% intermediate, and 2% high risk. The median dose was 36.25 Gy (35-40 Gy range) delivered either with 4 or 5 fractions. The prescribed dose groups were as follows: 35 Gy in 42%, 36.25 Gy in 47%, and >38 Gy in 11%. Androgen deprivation therapy was given to 21% of patients. Biochemical relapse, defined as a rise > 2 ng/ml above nadir, was determined in a total of 4 failures. Results: The median follow-up for all 135 cases was 60 months (range 60 to 72). For all patients, the bRFS rate at 5 years was 97%. The 5-year actuarial bRFS rates for GS < 6, and Gleason score 7 were 98%, and 92%, respectively (p=0.15). The 5-year actuarial bRFS rates for low versus intermediate/high-risk patients were 99% and 93%, respectively (p=0.11). The 5-year actuarial bRFS rates for patients receiving 35 Gy versus >36.25 Gy were 93% and 100%. No difference in bRFS was observed with the use of androgen deprivation (p=0.78). Multivariate analysis showed only GS to be an independent predictor of relapse (p=0.03); iPSA (p=0.10) and radiation dose (0.97) were not. Conclusions: In a relatively large cohort of localized prostate cancer patients treated with SBRT, long follow-up period (>5 years), excellent efficacy was demonstrated with 97% of patients being free from relapse. For low and intermediate risk cases, these results compare favorably with other modalities with similar follow-up periods. Although a trend for worse outcome was seen with total radiation doses of 35 Gy, this was not confirmed on multivariate analysis.

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