To identify a PSA threshold value at an intermediate follow-up time after low dose rate (LDR) prostate brachytherapy associated with cure, defined as long-term (10-15 year) freedom from prostate cancer.
Data from 7 institutions for 14,220 patients with localized prostate cancer treated with LDR brachytherapy, either alone (8552) or with external beam radiotherapy (n = 1175), androgen deprivation (n = 3165), or both (n = 1328), were analyzed. Risk distribution was 42.4% favorable, 49.2% intermediate, and 8.4% high-risk. Patients with clinical failure before 3.5 years were excluded. Kaplan-Meier analysis was used with clinical failure (local, distant, regional or biochemical triggering salvage) as an endpoint for each of four PSA categories: PSA ≤ 0.2, >0.2 to ≤0.5, >0.5 to ≤1.0, and >1.0 ng/mL. PSA levels at 4 years (±6 months) in 8746 patients without clinical failure were correlated with disease status at 10-15 years.
For the 77.1% of patients with 4-year PSA ≤ 0.2, the freedom-from-recurrence (FFR) rates were 98.7% (95% CI 98.3-99.0) at 10 years and 96.1% (95% CI 94.8-97.2) at 15 years. Three independent validation cohorts confirmed 97-99% 10-year FFR rates with 4-year PSA ≤ 0.2. Successive PSA categories were associated with diminished disease-free rates at 10 and 15 years. PSA category was strongly associated with treatment success (p < 0.0005).
Since 98.7% of patients with PSA ≤ 0.2 ng/mL at 4 years after LDR prostate brachytherapy were disease-free beyond 10 years, we suggest adopting this biochemical definition of cure for patients with ≥4 years' follow-up after LDR brachytherapy.
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2020 Apr 27 [Epub ahead of print]
Juanita M Crook, Chad Tang, Howard Thames, Pierre Blanchard, Jeremiah Sanders, Jay Ciezki, Mira Keyes, W James Morris, Gregory Merrick, Charles Catton, Hamid Raziee, Richard Stock, Frank Sullivan, Mitch Anscher, Jeremy Millar, Steven Frank
BC Cancer, University of British Columbia, Kelowna, Canada. Electronic address: ., MD Anderson Cancer Center, University of Texas, Houston, United States. Electronic address: ., MD Anderson Cancer Center, University of Texas, Houston, United States., MD Anderson Cancer Center, University of Texas, Houston, United States. Electronic address: ., Cleveland Clinic, Case Western Reserve University, Cleveland, United States. Electronic address: ., BC Cancer, University of British Columbia, Vancouver, Canada. Electronic address: ., BC Cancer, University of British Columbia, Vancouver, Canada., Schiffler Cancer Center, Wheeling, United States. Electronic address: ., University Health Network, University of Toronto, Canada. Electronic address: ., University Health Network, University of Toronto, Canada. Electronic address: ., Mt Sinai School of Medicine, NY, United States. Electronic address: ., National University of Ireland, Galway, Ireland. Electronic address: ., Alfred Health, Melbourne Australia. Electronic address: ., MD Anderson Cancer Center, University of Texas, Houston, United States. Electronic address: .