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.