Biennial vs. annual prostate biopsies: What the data show

Among men undergoing active surveillance for low-risk prostate cancer, biennial biopsies appear to be an acceptable alternative to annual biopsies.

Among men undergoing active surveillance for low-risk prostate cancer, biennial biopsies appear to be an acceptable alternative to annual biopsies, according to a retrospective review of four large surveillance cohorts.

Looking specifically at time to biopsy upgrade, “The consequences of more versus less frequent biopsies seem to be similar across cohorts,” investigators reported online in the Annals of Internal Medicine (Nov. 28, 2017).

These findings provide a “quantitative justification” for the recent American Society of Clinical Oncology practice guideline that recommends less frequent biopsies following a confirmatory biopsy within a year of starting active surveillance, said the study’s senior author, Ruth Etzioni, PhD, of Fred Hutchinson Cancer Research Center, Seattle.

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“A biopsy is not a trivial matter,” Dr. Etzioni said in an interview with Urology Times. “So if [the patient] is in a low-risk situation, we can now put some numbers around what the downside of less frequent biopsies will be in terms of the delay in treatment, and they're not very bad.”

The findings underscore the fact that active surveillance is “a very low-risk setting” with a low chance of an adverse disease-related outcome over the long term, Dr. Etzioni added.

To assess the impact of less frequent biopsies, Dr. Etzioni and colleagues statistically modeled the risk for biopsy upgrading in data from four active surveillance cohorts including 2,576 patients with T1 or T2 prostate cancer and a Gleason score between 2 and 6.

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Compared to annual biopsies, biennial biopsies starting after a first confirmatory biopsy were associated with short delays in detecting upgrading of about 3 to 5 months, depending on the cohort; that finding suggests the biennial practice is “justified,” according to the authors, particularly given the invasiveness and potential morbidity of annual biopsies.

The four active surveillance studies, conducted between 1995 and 2014, were conducted by Johns Hopkins University, Baltimore; Canary Prostate Active Surveillance Study (PASS); the University of California, San Francisco; and the University of Toronto.

Looking at data from different active surveillance cohorts provided a chance to look at the impact of active surveillance protocol on detection of disease progression, according to Dr. Etzioni.

Despite the “robust” consistency among cohorts in expected delays to detection of upgraded cancer, the authors noted that the risk for cancer upgrading was not generalizable among cohorts even after controlling for potentially confounding factors.

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"What it really tells us, ultimately, is that even when we try to put them on the level playing field, there are still differences,” Dr. Etzioni said.

That lack of consistency suggests ongoing “practical challenges” that will have to be addressed going forward, Dr. Etzioni and her colleagues said in the article.

Although the present findings do seem to confirm biennial biopsies are a reasonable alternative to annual biopsies, Dr. Etzioni suggested that in clinical practice, biopsy frequency might need to take into account patient preference.

“A lot of men do opt out, and we need to better understand that,” she said. “We need to better understand preferences and how they change over time. My feeling is that maybe we should be thinking more in terms of ‘inactive surveillance,’ particularly in older men who have other health conditions, because I think that there's also an element of anxiety associated with biopsy.”

Funding for the study came from the National Cancer Institute.