Presentation Authors: Mufaddal Mamawala*, Baltimore, MD, Jeffrey Tosoian, Ann Arbor, MI, Jonathan Epstein, Patricia Landis, Demetrios Simopoulos, Katarzyna Macura, Michael Gorin, H. Ballentine Carter, Baltimore, MD
Introduction: Active surveillance (AS) is a first-line management option for men with very low risk (VLR) and low risk (LR) prostate cancer. We sought to assess and describe long-term clinical outcomes and the optimal approach to AS.
Methods: Prospectively-defined cohort study initiated in January 1995 and followed clinically through July 2018, comprised of men diagnosed with VLR (n=1293) or LR (n=525) prostate cancer who elected initial management with AS in favor of immediate definitive therapy. The 10- and 15-year cumulative incidence were evaluated using a competing risk analysis for primary outcomes: all-cause mortality, prostate cancer-specific mortality or metastatic disease; and secondary outcomes: biopsy grade reclassification (BGR) to Grade Group (GG) â‰¥ 2, BGR to GG â‰¥ 3, and curative intervention. Additionally, the use of targeted biopsy was assessed.
Results: 1818 men (median age 66, IQR 61 -69) were enrolled in AS during the study period with a median follow-up of 5.0 years (range 0.01-20.0); 920 men â‰¥5 years and 305 â‰¥10 years. The median interval between surveillance biopsies was 13 months (IQR 12 -15). There were 88 deaths due to causes other than prostate cancer, 4 deaths due to prostate cancer, and a total of 10 patients who experienced prostate cancer death or metastatic disease (6 VLR and 4 LR). The cumulative incidence of prostate cancer death or metastasis was 0.6% at 10 years and 1.4% at 15 years. The cumulative hazard ratio of non-prostate-cancer death to prostate cancer death or metastasis was 26:1 (Figure). The 10- and 15-year cumulative incidence of BGR to GG â‰¥ 2, BGR to GG â‰¥ 3, and curative intervention was 30% and 32%; 10% and 11%; and 48% and 52%, respectively. The median treatment free survival was 11 years. Since it was introduced, the use of targeted biopsy significantly increased from 21% in 2014 to 36% in 2017 (p= < 0.001), while misclassification rates, i.e., BGR within first 2 surveillance biopsies, significantly decreased from 21% in 2014 to 7% in 2017 (p = 0.002).
Conclusions: In a large, single-institution, prospective AS cohort under careful monitoring, the risk of cancer death or metastasis was low over long-term follow-up. These data continue to support the use of AS in the management of most patients with favorable-risk prostate cancer.