Despite increasing adoption of active surveillance (AS) for low-risk prostate cancer, AS discontinuation rates are high, investigators report.
Among 16,852 men diagnosed with Gleason score 6 or lower prostate cancer from 2008 to 2014 in Ontario, Canada, 8541 (51%) chose AS for initial management. Use of AS significantly increased over the period from 38% to 69%. Men who selected AS at diagnosis were significantly older than men who selected initial treatment: mean 64 vs 62 years.
After a median 48 months, 4337 (51%) patients discontinued AS, Antonio Finelli, MD, of the University of Toronto in Ontario, Canada, and colleagues reported in The Journal of Urology. Median time to definitive treatment after initial AS was 16 months. Treatment-free survival rates for AS patients at 1, 3, and 5 years were 85%, 58% and 52%, respectively.
On multivariable analysis, patient factors significantly associated with greater AS discontinuation included age younger than 55 years at diagnosis, diagnosis in 2008-2011 vs 2012-2014, and higher comorbidity scores, the investigators reported. Treatment at an academic vs nonacademic center was significantly associated with a significant 31% increased risk of discontinuation. Treatment by a radiation oncologist vs urologist was significantly associated with a 2.2-fold increased risk of AS discontinuation. Receiving treatment from physicians or institutions in the highest-volume tertile also correlated with a switch to definitive treatment.
With respect to disease characteristics, PSA higher than 4 ng/mL, more than 1 positive core, and more than 50% of the core involved by cancer at diagnosis all significantly associated with definitive treatment. Half of patients who went on to treatment experienced grade group progression.
“Our study demonstrated that, in a real-world setting across many institutions and providers, the long-term discontinuation rate is significant (52% at 5 years); whereas studies from single institution academic centers report lower discontinuation rates (24%–41%),” Dr Finelli’s team wrote. “This has implications for patient counseling and setting realistic expectations.”
The investigators were unable to assess the role of biomarkers and MRI in patient selection for AS. Patients who chose watchful waiting were excluded from the study.
Timilshina N, Komisarenko M, Martin LJ, et al. Factors associated with discontinuation of active surveillance among men with low-risk prostate cancer: a population-based study. J Urol. 2021 Oct;206(4):903-913; published online August 20, 2021. doi:10.1097/JU.0000000000001903