Yearly Biopsy Not Needed for Prostate Cancer Surveillance

Nick Mulcahy

November 29, 2017

It is "acceptable" to perform a biopsy on men every 2 years instead of annually when they have low-risk prostate cancer and are being managed with active surveillance, concludes a new analysis that integrates individual patient data from four major ongoing studies.

The delay in detecting disease progression with biennial testing, relative to annual testing, ranges from 3 to 5 months, which is "modest" and is very unlikely to influence a patient's long-term outcome, said senior author Ruth Etzioni, PhD, a biostatistician at Fred Hutchison Cancer Research Center in Seattle, Washington.

The findings are important because there is no consensus about implementing the relatively new approach of active surveillance, including the timing of the multiple-core needle biopsy, which is invasive and is associated with potential risks.

Given the natural history of prostate cancer, a delay of 6 months or less in detecting disease progression is not going to change the final outcome in the "vast majority of cases," Dr Etzioni told Medscape Medical News. "Yet it halves the number of times a patient has to come for a biopsy [over the years]."

She also pointed out that the cancer upgrades are "generally" from Gleason scores of 3+3 to 3+4, which would lead to a reclassification of a patient's disease from low risk to intermediate risk.

The new analysis was published online November 28 in the Annals of Internal Medicine.

The authors examined data from the four biggest active surveillance cohorts in North America: Johns Hopkins University; Canary Prostate Active Surveillance Study; University of California, San Francisco (UCSF); and the University of Toronto.

The various sites differ with regard to schedules for planned biopsies; periods range from every 4 years at Toronto to annually at Johns Hopkins, although not all patients at each center are managed as planned.

The investigators compared prostate-specific antigen (PSA) levels and biopsy Gleason scores for 2576 men who were enrolled in an active surveillance protocol at the four sites between 1995 and 2014. All of the men had low-risk disease: a Gleason score between 2 and 6 and T1 or T2 prostate cancer.

The team reports that the consequences of annual vs biennial biopsies were similar across four separate cohorts of men: all of the delays in detecting progression were less than 6 months. In comparing biennial with annual biopsies, the mean delay in upgrade detection was highest at Johns Hopkins, at about 5 months; the lowest delay was at the University of Toronto and UCSF, at about 3 months.

The delays in detecting prostate cancer cases that warranted upgrading, under more frequent vs less frequent biopsy protocols, are a "robust finding" across the cohorts, said Dr Etzioni.

The study authors say that this finding provides "quantitative justification" for the recent statement from the American Society of Clinical Oncology (ASCO) on active surveillance for early prostate cancer (J Clin Oncol. 2016;34:2182-90). That ASCO statement endorsed the Cancer Care Ontario guideline, which recommends less frequent biopsies after confirmatory biopsy within a year of entering active surveillance.

Ronald C. Chen, MD, MPH, the lead author of the ASCO statement, who is associate professor of radiation oncology at the University of North Carolina Lineberger Comprehensive Cancer Center in Durham, confirmed the study authors' assessment.

"Data from this new study demonstrate that annual biopsies are not necessary," Dr Chen told Medscape Medical News in an email.

Data from this new study demonstrate that annual biopsies are not necessary. Dr Ronald Chen

He explained that the new study supports the ASCO guidance, which recommends an initial confirmatory biopsy within 6 to 12 months, followed by repeat biopsies every 2 to 5 years.

Urologists at Dr Chen's North Carolina center usually recommend biopsies every 2 to 3 years, he added.

Approached for comment, Elizabeth Heath, MD, professor of oncology and medicine at the Karmanos Cancer Institute at Wayne State University in Detroit, Michigan, said use of less frequent biopsies after a confirmatory biopsy within a year of entering surveillance is "reasonable."

She also said use of less frequent biopsies should not unduly expose urologists to possible lawsuits. "I don't see any major legal vulnerabilities with this approach," she said in an email.

Risks for Upgraded Cancer

Notably, in the new analysis, after the researchers accounted for variables in the protocols and competing treatments, risks for upgrading or progression differed among patients in the four active surveillance cohorts.

Variables such as eligibility criteria and the indicators that trigger a recommendation for definitive treatment are complex, suggest the authors.

The risk for cases being upgraded was highest in the UCSF cohort and lowest at Johns Hopkins. The risk at Toronto was similar to that reported in the Canary Prostate Active Surveillance Study.

However, when the researchers removed the variable regarding competing treatments, differences in upgrading rates dramatically emerged among the cohorts. For example, the 10-year cumulative risk for upgrading in the absence of competing treatments ranged from 25% at Johns Hopkins to 65% at UCSF.

The authors speculated that uncaptured differences in patient profiles among the four cohorts may be at play. For example, the Johns Hopkins patients all had very-low-risk prostate cancer, with low PSA densities (<0.15 ug/L per mL), which in turn may result from a higher prostate volume. Thus, in men with more voluminous prostates, it is likely that the chance of identifying high-grade foci is reduced, the study authors point out.

Overall, the authors caution that findings from a single active surveillance cohort may not reflect the risks for prostate cancer progression in another study population.

The study authors were supported by grants from the National Cancer Institute and other organizations. Dr Etzioni has disclosed no relevant financial relationships. Several coauthors report relationships with pharmaceutical companies or genetics testing companies, as listed in the original article. Dr Chen has received grants and personal fees from Accuray and personal fees from Astellas and Medivation. Dr Heath has disclosed no relevant financial relationships.

Ann Intern Med. Published online November 28, 2017. Abstract

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