Comparative efficacy of local versus systemic salvage therapies for recurrent prostate cancer after primary radiotherapy.

Authors

null

Glenn Bauman

Western University, London Regional Cancer Program, London, ON, Canada

Glenn Bauman , Keyue Ding , Joseph Chin , Alessandra Iaboni , Laurence Klotz , David P. Dearnaley , Eric M. Horwitz , Juanita M. Crook , Christopher J. O'Callaghan

Organizations

Western University, London Regional Cancer Program, London, ON, Canada, Canadian Cancer Trials Group, Kingston, ON, Canada, London Health Sciences Centre, London, ON, Canada, Department of Public Health, Kingston, ON, Canada, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada, Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom, Fox Chase Cancer Center, Philadelphia, PA, The University of British Columbia, Kelowna, BC, Canada, Queen's University, Canadian Cancer Trials Group, Kingston, ON, Canada

Research Funding

Other
Sanofi CARO GU research grant.

Background: We sought to compare two common salvage strategies for radio-recurrent prostate cancer: androgen deprivation therapy (ADT: PR7 RCT NCT00003653) or local salvage ablation using cryotherapy (CRYO: single institution study Williams, Eur Urol. 2011;60(3):405). Methods: Pre-salvage therapy prognostic variables common to the two datasets (Gleason score at initial treatment, time from original RT, use of ADT at time of original RT, PSA at time of salvage, patient age) were used for propensity matching between patients from previously published ADT (1) and CRYO (2) datasets. Progression free survival (PFS, defined as time from initial treatment to development of castrate resistance or death); Disease Specific Survival (DSS, defined as time from salvage to prostate cancer related death) and Overall Survival (OS, defined as time from salvage to death from any cause) were compared between the propensity matched cohorts using Log-Rank and Cox PH regression statistics. Raw linear propensity scores included in the PH model to account for residual variability. A planned subset analysis examined the effect of neoadjuvant ADT among the CRYO cohort (no CRYO patients had adjuvant ADT). Results: Overall, 1119/1386 (ADT) and 172/187 (CRYO) patients were included in the propensity matched analysis. Median follow up was 6.7 yrs (ADT) and 18.7 yrs (CRYO). Median PFS (95% CI) was 10.7 yrs (9.5, 12.3) for CRYO vs. 7.0 yrs (6.1, 10.0) for ADT (HR 0.63 (0.44, 0.89), p = 0.009). Median OS was also longer for CRYO vs. ADT: 12.3 (11.0, 13.8) vs. 10.2 (9.4, not reached) yrs (HR 0.69; p = 0.02). 10 year DSS event rate was 16.5% CRYO vs. 18.5% ADT but was not statistically different. Neoadjuvant ADT did not affect outcomes in CRYO. Conclusions: A 3-year PFS and 2-year OS benefit was noted for the CRYO vs. ADT cohorts while no difference was noted in DSS. Potential explanations include residual bias not corrected for in the propensity scoring, variable follow-up duration, adverse effects from differing cumulative exposure to ADT or a combination of these factors. Prospective comparisons are required to control for these potential biases and compare other important outcomes such as side effects and quality of life.

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Abstract Details

Meeting

2020 Genitourinary Cancers Symposium

Session Type

Poster Session

Session Title

Poster Session B: Prostate Cancer; Urothelial Carcinoma; Penile, Urethral, Testicular, and Adrenal Cancers

Track

Urothelial Carcinoma,Adrenal Cancer,Penile Cancer,Prostate Cancer - Advanced,Prostate Cancer - Localized,Testicular Cancer,Urethral Cancer

Sub Track

Patient-Reported Outcomes and Real-World Evidence

Citation

J Clin Oncol 38, 2020 (suppl 6; abstr 221)

Abstract #

221

Poster Bd #

A21

Abstract Disclosures