Low-Risk Prostate Cancer May Merit Less Frequent Biopsies
NEW YORK (Reuters Health) - Biopsies every 2 years, instead of annually, seem to be "an acceptable alternative" for acute surveillance of low-risk prostate cancer, according to a comparative analysis.
"Given that patients on active surveillance are very low risk, less might be more in strategizing how to manage these patients,” Dr. Ruth Etzioni from Fred Hutchinson Cancer Research Center, Seattle, Washington, told Reuters Health by email.
While active surveillance is increasingly adopted for managing low-risk prostate cancer, there is no consensus about how exactly to implement it.
Dr. Etzioni and colleagues assessed the risks of prostate biopsy upgrading - from a Gleason score of 6 or less to a score of 7 or more - across four prostate cancer active surveillance cohorts. The cohorts involved 2,576 men (ages 40-80) with an initial Gleason score of 2 to 6 and clinical stage T1 or T2 prostate cancer.
The study's findings were published online November 27 in Annals of Internal Medicine.
The mean prostate-specific antigen (PSA) velocity was similar (range, 5% to 8%) across cohorts from Johns Hopkins University (JHU); University of California, San Francisco (UCSF); University of Toronto (UT); and the Canary Prostate Active Surveillance Study (PASS).
After accounting for the cohorts' eligibility criteria, surveillance intervals, and how progression of cancer was defined, the estimated 10-year cumulative risk for upgrading was highest at UCSF (65%) and lowest at JHU (25%), with similar intermediate risks between UT and PASS.
“It is interesting that even when you put the different cohorts on a level playing field in terms of inclusion criteria and surveillance schedules and progression definition, you don’t end up with comparable results,” Dr. Etzioni said. “So, we conclude that one should probably not predict the absolute risk of progression or downstream outcomes based on a single cohort. Or if one does, then one should realize that it may not be applicable to your case.”
Biennial biopsies starting at enrollment reduced the number of biopsies relative to annual biopsies by 42% to 48% but delayed detection of upgrading by 6 to 8 months. Biennial biopsies beginning 1 year after enrollment reduced the number of biopsies by 32% to 38% while delaying detection of upgrading by only 3 to 5 months.
Delayed detection was associated with an increased risk of death from prostate cancer, but this increase was under 3% across cohorts for delays ranging from 1 to 4 years.
“Our study is more about best active surveillance in general, and we have concluded that in general one can consider less frequent rather than more frequent biopsies,” Dr. Etzioni said. “But other models are trying to make active surveillance more personalized. Based on a person’s accumulating PSA levels and biopsy results, these models aim to predict the risk of progression at the scheduled biopsy time and allow the patients and provider together to decide whether they are comfortable extending the interval until the next biopsy. These models are quite complicated and are still under development.”
“In general,” she said, “it seems that patients do not need to have an annual biopsy, and that if accumulating PSA and biopsy results are favorable, patients may be able to lengthen intervals between their biopsies even further.”
Dr. Soroush Rais-Bahrami from University of Alabama at Birmingham, who recently reviewed prostate cancer imaging and biomarkers for guiding active surveillance, told Reuters Health by email, "The data from all four robust active surveillance series investigated for this project support spacing out biopsy intervals to every other year after the first year’s confirmatory biopsy. This was shown to be safe without causing a clinically significant delay in detecting prostate cancer upgrading.”
“The paper demonstrates how a variety of inclusion criteria have been used in programs with successful, longstanding active surveillance protocols,” he said. “The best active surveillance protocol depends on a personalized approach derived between patients and their physicians holding a discussion of the risks when expanding inclusion criteria while achieving the potential benefit of quality-of-life measures, even if temporary before potentially needing definitive treatment.”
“Active surveillance is a safe, viable option in this new era of prostate cancer management, demonstrated to be safe if implemented wisely in a personalized, case-based manner,” Dr. Rais-Bahrami concluded. “The goal is to preserve optimal quality of life while not compromising timely cancer care.”
Ann Intern Med 2017.