Online

WCB 2021 - Online

Session Item

Thursday
May 06
14:15 - 15:30
This house believes that combination therapy for intermediate and high-risk prostate cancer represents best standard of care
Peter Hoskin, United Kingdom;
Yasuo Yoshioka, Japan
0091
Debate
14:15 - 14:30
This house believes: Combination therapy for intermediate and high-risk pCa represents the best standard of care
Mira Keyes, Canada
SP-0029

Abstract

This house believes: Combination therapy for intermediate and high-risk pCa represents the best standard of care
Authors: Mira Keyes(BC Cancer, Radiation Oncology, Vancouver, Canada)
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Abstract Text

Combination of brachytherapy boost and external beam radiation with or without androgen deprivation therapy (ADT) has been an excellent treatment option for men with high intermediate risk and favorable high risk patients.  The treatment outcomes with brachytherapy including long term PSA control, metastatic free survival, cause specific survival and ultimately cure rates with any form of brachytherapy are very high.  The superior disease outcomes are confirmed in numerous institutional reports, large US database queries, systemic overviews, and 3 randomized controlled trials (RCT) comparing EBRT with or without PB boost.  From all levels of evidence, the congruence of results is remarkably high.  The American Society of Clinical Oncology (ASCO), Cancer Care Ontario (CCO), American Brachytherapy Society (ABS), NCCN and ASTRO all endorse EBRT and PB boost as a standard management for high-tier intermediate and high-risk PCa. The ongoing RCT are in progress to determine the role of ADT, duration of ADT, the role of pelvic radiation.  

 

However, dose escalation with brachytherapy boost has not been shown to increase the overall survival. There is an ongoing debate on most appropriate end points when considering PCa treatment outcomes. While OS is the most robust in many disease sites, it fails to address numerous issues including; long natural history of Pca, advanced age at diagnosis, effects of commodities on outcomes, availability of new and more effective systemic treatment for metastatic disease, poorly researched and documented cost to the health care system of additional morbidity and detrimental quality of life outcomes associated with local and systemic salvage treatments. 

 

Increased toxicity of brachytherapy boost has been a concern used as a reason to consider alternative, less effective treatments for high risk disease, including EBRT or radical prostatectomy.   One must keep in mind that the reported brachytherapy boost Gr 3 toxicity prevalence rate is markedly less than the late grade 3 toxicity, after radical prostatectomy, as reported in published RCTs. Addition of EBRT in adjuvant or salvage setting further contributes to long term toxicity. New radiation fractionation schemes and SBRT lack long term disease and toxicity outcomes in high risk disease. 

 

Brachytherapy is the most effective radiation treatment for localized PC. Brachytherapy boost significantly increase PSA recurrence free survival, obviating the need for expensive investigation for PSA recurrence, toxic local salvage treatments, and expensive and toxic lifelong systemic treatments. Brachytherapy boost should be only offered to younger patents with good urinary function and good life expectancy, where the trade-off between of up front higher toxicity vs. lifelong toxic systemic treatment for failure to cure, is favorable.