Prostate cancer (PCa) patients on active surveillance (AS) who have no cancer found on a confirmatory biopsy may be considered for a less rigorous AS regimen, according to investigators.
In a study of 224 PCa patients managed with AS, investigators at Cleveland Clinic led by Ryan Berglund, MD, found that absence of cancer on a confirmatory biopsy is associated with a significant 49% decreased odds of grade reclassification and 68% decreased odds of volume reclassification compared with those who had a positive confirmatory biopsy.
“Overall, our findings suggest that very low volume disease, reflected by a negative confirmatory biopsy, may be a strong prognostic indicator for slower grade and volume reclassification, independent of age, PSA density, and stage,” Dr Berglund’s group wrote in a paper published online ahead of print in Urology. “It is possible that very low volume of disease may exhibit a more indolent natural history.”
The investigators concluded that a less intense surveillance regimen may be considered for men with a negative confirmatory biopsy.
Of the 224 patients, 111 (49.6%) had a negative confirmatory biopsy. The remaining 113 patients had stable disease on confirmatory biopsy. The median follow-up was 55.8 months.
The typical AS regimen at Cleveland Clinic consists of clinic visits ever 6–12 months with PSA measurements and digital rectal examinations, a confirmatory biopsy within 12 months of the initial diagnostic biopsy, and routine surveillance biopsies, the researchers stated.
Dr Berglund and his colleagues said their results are comparable to those of previous studies. For example, a single-institution retrospective study of 286 AS patients by Lih-Ming Wong, MD, and colleagues showed that men with no cancer found on a second biopsy had a 53% reduction in overall risk of reclassification, according to a report in European Urology (2014;66:406-413). A subset analysis revealed a 64% decreased risk of volume-related reclassification, but, contrary to the findings of the new study, no significant association with risk of grade reclassification.
Dr Berglund’s team also cited a study by K. Clint Cary, MD, and colleagues, which found that among 242 men with 3 or more biopsies, a negative confirmatory biopsy was associated with 72% lower odds of overall reclassification. That study, which was published in European Urology (2014;66:337-342), did not differentiate between grade- and volume-related reclassification.
Dr Berglund and his colleagues acknowledged some study limitations. The study was observational and, as such, subject to selection bias “and imbalance in unquantified variables.” In addition, the limited median follow-up time of 55.8 month may not fully capture the natural history of slow-progressing PCa. Third, it remains to be determined how the endpoints of grade and volume reclassification ultimately will reflect overall or cancer-specific survival.
Ganesan V, Dai C, Nyame YA, et al. Prognostic significance of a negative confirmatory biopsy on reclassification among men on active surveillance. Urol [Epub ahead of print].