Presentation Authors: Patrick Richard, Saint-denis-de-Brampton, Qc, Canada, Narhari Timishina, Maria Komisarenko, Lisa Martin, Ardalan Ahmad*, Shabbir Alibhai, Robert Hamilton, Girish Kulkarni, Antonio finelli, Toronto, Canada
Introduction: Prostate cancer is the most common solid organ cancer among North American men. Traditionally, men diagnosed with prostate cancer were offered treatments in the form of radical prostatectomy, external-beam radiotherapy or brachytherapy. However, natural history studies have shown that only a minority of those with low or intermediate risk disease will develop metastases and/or succumb to the cancer. Thus, active surveillance has become an accepted strategy for low-risk, but debated as to its application in intermediate-risk prostate cancer. Unfortunately, most reports of intermediate-risk prostate cancer managed by active surveillance generally lack long-term follow-up and include small numbers of patients. Thus, the objective of this population-based study was to report the long-term outcomes of men diagnosed with Grade Groups 2 and 3 prostate cancer who were managed expectantly.
Methods: Using administrative datasets and pathology reports, we identified all men who were diagnosed with Grade Groups 2 and 3 prostate cancer and managed expectantly between 2002 and 2011 in Ontario, Canada. The overall survival, cancer-specific survival and treatment-free survival were estimated using cumulative incidence function methods while their associated factors were estimated multivariable Cox regression models.
Results: We identified 926 men with GG2 or GG3 PCa that were managed expectantly (Active surveillance (n=374) or watchful waiting (n=552)). The 8-year cancer-specific survival was 94% and 89% for the active surveillance and watchful waiting cohorts, respectively. Among men managed by active surveillance, 266 (71%) received treatment after a follow-up of approximately 8 years. Cumulative active surveillance discontinuation rates at 1- and 5-years were 30.5% and 65.1%, respectively.
Conclusions: Expectant management of Grade Groups 2 and 3 PCa may be an option for certain men. Notably for active surveillance patients, the cancer-specific mortality at 8-years was 6%. More importantly, over 65% of men underwent treatment within 5 years. Further studies are required to evaluate which sub-group of patients, based on disease-specific features and competing health risks, would benefit the most from this strategy.
Source of Funding: Prostate Cancer Canada