Participants for this study were prospectively enrolled in an active surveillance study on protocol-directed follow-up at 10 centers nationwide. The flow diagram of the study is as follows:
The authors included those who had grade group 1 or grade group 2 at diagnosis and at least one confirmatory biopsy. Patients were stratified according to grade group at diagnosis and whether they were reclassified from initial biopsy. The primary outcome was treatment-free survival, and secondary outcomes included adverse pathology at radical prostatectomy, and biochemical recurrence after treatment. Time from diagnosis to treatment and time from definitive treatment to biochemical recurrence were evaluated using the Kaplan-Meier method; adverse pathology at radical prostatectomy, defined as grade group ≥3, ≥pT3a, or pN1, was analyzed as interval-censored data using Weibull regression.
Between August 2008 and February 2019, 1,557 patients met the eligibility criteria. At diagnosis, 1426 (92%) patients had grade group 1 and 131 (8%) had grade group 2, out of which 99 (76%) presented with a single core of grade group 2. Patients with grade group 2 were older (66 vs 62 years) and had a shorter median follow-up (5.5 vs 6.8 years) compared to grade group 1 patient. Reclassification rate at 5 years occurred in 36% of grade group 2 and 38% of grade group 1 patient. Overall, patients with grade group 2 had a shorter time to treatment compared to patients with grade group 1 (median 4.3 vs. 10.3 years p<0.0001):
Among those who were not reclassified, patients with grade group 2 had a shorter time to treatment compared to grade group 1 (median 4.55 vs not reached), but had a longer time to treatment compared to grade group 1 and grade group 2 who got reclassified:
The risk of adverse pathology at radical prostatectomy was slightly higher for grade group 2 than for grade group 1 (HR 1.37, 95% CI 0.73 – 2.54), but not statistically significant. Biochemical recurrence within 3 years of treatment among those treated with surgery or radiation for grade group 2 was 10% and for grade group 1 was 13% (p=0.50).
Dr. Waisman Malaret concluded this presentation with the following take-home messages:
- Most grade group 2 patients enrolled in the PASS active surveillance protocol had low volume grade group 2 disease
- Low volume grade group 2 patients on active surveillance are more likely to undergo treatment and on a short interval than grade group 1 patients
- Adverse pathology after radical prostatectomy and biochemical recurrence after definitive treatment are similar in low volume grade group 2 patients compared to grade group 1 patients
- Active surveillance patients with low volume grade group 2 will have a shorter time to treatment, however, limited follow-up post-treatment suggest equal oncologic outcomes
Presented by: Adrian J. Waisman Malaret, MD, Beth Israel Deaconess Medical Center, Brookline, Massachusetts
Co-Authors: Kehao Zhu, Yingye Zheng, Lisa Newcomb, Peter Chang, Kolawole O. Olugbade Jr., James D. Brooks, Peter Carroll, Atreya Dash, Cristopher P. Filson, Martin E. Gleave, Michael Liss, Frances M. Martin, Todd M. Morgan, Peter S. Nelson, Daniel W. Lin, Andrew A. Wagner
Written by: Zachary Klaassen, MD, MSc – Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, Twitter: @zklaassen_md at the 2020 American Urological Association (AUA) Annual Meeting, Virtual Experience #AUA20, June 27- 28, 2020
References:
1. Klotz L, Vesprini D, Sethukavalan P, et al. Long-term follow-up of a large active surveillance cohort of patients with prostate cancer. J Clin Oncol 2015;33(3):272-277.
2. Yamamoto T, Musunuru HB, Vesprini D, et al. Metastatic prostate cancer in men initially treated with active surveillance. J Urol 2016 May;195(5):1409-1414.