Biopsy May Underestimate Prostate Cancer in Larger Men

Biopsies for prostate cancer in men who are overweight or obese may be misleading and may underestimate how aggressive the tumor really is, which in turn could result in treatment that is inadequate or inappropriate. This is one of the clinical implications of a new finding reported in the March issue of Urology. "We must keep in mind that even if a well-done biopsy shows a low-grade cancer in an obese patient, there is still a reasonable likelihood that the patients may have high-grade disease," says the lead author, Stephen Freeland, MD, from the Duke University Prostate Center, in Durham, North Carolina. "If we can determine through additional biopsies that an obese or overweight man has more aggressive prostate cancer, we can discuss whether the cancer should be treated with more than 1 approach, such as combining hormonal therapy with radiation," he commented in a press release. In the past, biopsy for prostate cancer was based on a standard of 6 samples, and some people still do that, but this is inadequate, Dr. Freeland told Medscape. The normal procedure today is to take 10 to 12 samples, but for obese men or those with large prostates, he recommends 14. Study Identified Discrepancies The finding comes from a study of 1100 men with prostate cancer who were identified in the Shared Equal Access Regional Cancer Hospital (SEARCH) database, which covers several hospitals in the California area as well as Durham.All the men had undergone a radical prostatectomy (RP). Dr. Freeland and colleagues compared the results obtained on examining the removed prostate tissue with the results obtained from biopsies performed before the operation and found discrepancies. The Gleason grading for the tumor matched in only 62% of cases. Most of the mismatched cases were upgraded (27%), as the grading of the tumor on RP was higher than that from the biopsy. Relatively few cases (11%) were downgraded. After adjustment for clinical covariates, upgrading was associated with an increased risk for biochemical progression, and downgrading was associated with a decreased risk for progression