Debating the Frequency of Biopsy in Monitoring Low-Risk Prostate Cancer

Study sheds new light on optimal timing

A recent study of 300 men on active surveillance for low-risk prostate cancer revealed something that may come as a surprise: urologists are likely ordering too many biopsies.

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“The generally accepted practice is to perform surveillance biopsies every two years, regardless of disease status, but that practice comes more from providers feeling uncomfortable waiting any longer—not because of any studies connecting biopsy intervals with overall survival,” says urologist Andrew Stephenson, MD, from Cleveland Clinic Glickman Urological & Kidney Institute who is senior author on the study.

In fact, when Dr. Stephenson and collaborators conducted a literature review, they could find no studies to support the widely adopted two-year practice. It’s a big question in urology that, until now, has been insufficiently evaluated.

The new study is published in the Journal of Urology and shows that the overwhelming majority of men on active surveillance (about 84 percent) have stable disease at the time of initial two-year surveillance biopsy.

Furthermore, almost none of the men who had stable disease at initial surveillance biopsy are liable to experience a change in disease state within the subsequent five years, suggesting the two-year biopsy interval may be safely extended after initial surveillance.

When the second surveillance biopsy was deferred for five years (instead of the usual two years), the chances of biochemical progression-free survival was 89 percent, according to the study.

In other words, “Men with stable disease at initial surveillance biopsy can probably wait at least five years, maybe longer,” says Dr. Stephenson. “Our overall message is that we’re ordering too many biopsies and we should probably be monitoring patients with other, less-invasive tools.”

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Support surveillance, use alternative tools

Surveillance protocols after the initial two-year surveillance biopsy should rely more heavily on regular PSA checks, prostate exams, and possible MRIs, says Dr. Stephenson.

“We’re fully supportive of active surveillance for men with low-risk prostate cancer, and we’ve found that ongoing ordering biopsies every two years is overly cautious and may have the unintended consequence of steering patients away from surveillance because of the high treatment burden,” says Dr. Stephenson. “Our analysis shows that you have to see a lot of patients before coming across one who would actually benefit from having the follow-up surveillance biopsy after two years.”

Results

Among the 251 (84 percent) patients who had no disease reclassification at initial surveillance biopsy, 35 (14 percent) and 11 (4 percent) demonstrated type I and type II disease reclassification on subsequent biopsy, respectively. Among the 122 men with disease-negative initial surveillance biopsy these rates were 12 percent (14) and 3 percent (3), respectively.

Among patients without disease reclassification on initial surveillance biopsy, the two-year actuarial rates of type I and II disease reclassification were 17 percent and 3 percent, respectively. For those with negative initial surveillance biopsy, the two-year actuarial rate of type I and type II reclassification was 11.3 percent and 0 percent, respectively.

In Dr. Stephenson’s study, 93 patients received deferred therapy. Their five-year biochemical progression-free probability was 89 percent, including 95 percent, 82 percent and 70 percent among those without and those with type I and type II disease reclassification, respectively.

In addition to provider uncertainty, patient anxiety contributes to discontinuation of active surveillance.

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To counter these concerns, Dr. Stephenson suggests a combination of molecular, genomic and imaging protocols that can also effectively monitor disease.

Further study needed

Dr. Stephenson stresses the importance of further studies to refine the approach to biopsy during active surveillance.

“Of course, the goal is to identify changes in disease state as quickly as possible, and we’ve always considered biopsy a critical tool in disease monitoring,” says Dr. Stephenson. “As it turns out, that often isn’t the case.”

What is needed now are more studies to connect genomic tests, imaging modalities, PSA screens, and other approaches with the need for confirmatory biopsy.

“Biopsy remains the gold standard in evaluating disease for treatment recommendation,” says Dr. Stephenson. “What we need are more studies that tell us when it’s appropriate to conduct a biopsy versus when we’re exposing the patient to unnecessary discomfort and risk of complication.”

Reprinted from Kovac E et al, Outcomes of active surveillance after initial surveillance prostate biopsy, J Urol, Jan 2017.