AUA 2017: Identifying the Optimal Candidate for Early Salvage Radiation Therapy after Radical Prostatectomy for Prostate Cancer: A Long-Term Multi-Institutional Analysis

Boston, MA (UroToday.com) For prostate cancer (PC) patients undergoing radical prostatectomy (RP), secondary therapies such as radiation therapy offers a second opportunity for definitive treatment. While the NCCN, EAU, and AUA guidelines specify risk factors associated with the need for adjuvant radiation therapy (RT), guidelines regarding the efficacy of salvage RT have only been explored in a subset of patients. Dr. Nicola Fossati from Milan, Italy presents a multi-center experience of patients with biochemical recurrence (BCR) post-RP and their corresponding effort to identify the optimal candidate for salvage RT.

693 node-negative RP patients who received salvage RT at six centers were included in analysis at a median follow-up of 96 months. Inclusion criteria for salvage RT included a rising PSA post-RP or PSA persistence at >0.09 ng/mL at 1 month post-RP. A risk stratification tool was developed with a study endpoint of cancer progression to metastasis post-salvage RT (M1a, M1b, or M1c). Multivariate analysis adjusted for pathologic t-stage, pathologic Gleason, surgical margins, post-operative undetectable PSA, and PSA level at salvage RT.

Of the 693 patients, 82 (12%) patients progressed to distant metastasis: 18 (2.6%) M1a, 33 (4.8%) M1b, and 9 (1.3%) M1c. Five risk groups were identified with regression tree analysis, of which the cohort was subdivided as follows:
1) very low-risk (42%): undetectable PSA after RP, Gleason sum ≤7, and ≤pT3a
2) low-risk (30%): undetectable PSA after RP, Gleason sum ≤7, and ≥pT3b
3) intermediate-risk (16%): undetectable PSA after RP, and Gleason sum ≥8
4) high-risk (8%): PSA persistence after RP, and Gleason sum ≤7)
5) very high-risk (3%): PSA persistence after RP, and Gleason sum ≥8.

Overall metastasis-free survival at 8 years was 86%, 75%, 74%, 72%, and 60%, respectively (p=0.003), with significant association with PSA level at the time of SRT. Early SRT was associated with treatment control and lower risk of distant metastasis in the low, intermediate, and high-risk patients, although there was no effect in both the very low and very high-risk patients. While further validation is necessary before expansion to the clinical setting, Dr. Fossati and colleagues present a valuable tool for patients experiencing BCR post-RP.

Presented by: Nicola Fossati (MD) from Milan, Italty

Authors: Nicola Fossati, Jeffrey Karnes, Stephen Boorjian, Michele Colicchia, Alberto Bossi, Thomas Seisen, Villejuif, France, Cesare Cozzarini, Claudio Fiorino, Barbara Noris Chiorda, Giorgio Gandaglia, Thomas Wiegel

Written By: Linda Huynh (BS), an assistant research specialist from the University of California, Irvine, on behalf of UroToday.com

at the 2017 AUA Annual Meeting - May 12 - 16, 2017 – Boston, Massachusetts, USA

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