Needle biopsy size and pathological Gleason Score diagnosis: No evidence for a link

Background: Biopsy Gleason score (GS), in combination with other clinical parameters, is important to take a therapeutic decision for patients with diagnosis of localized prostate cancer. However, preoperative GS is often upgraded after a radical prostatectomy. Increasing the amount of tissue in prostate biopsy may be a way to avoid this issue. We evaluate the influence of a larger biopsy needle size on the concordance between biopsy and pathological GS. Methods: We analyzed paired biopsies and prostatectomy specimens from 104 cases of men with clinically localized prostate cancer. At the time of prostate biopsy, the patients were prospectively randomized into two needle groups (16-Gauge [G] and 18G) using a 1:1 ratio. GS concordance was estimated performing kappa statistic testing, overall concordance rate and risk to under grade biopsy GS=6. A logistic regression analysis was performed to evaluate the patients' characteristics as possible risk factors. Results: The overall concordance between prostate biopsy and pathological GS was 76.9% and 75.6% (p = 0.875) and the k values were 0.821 and 0.811 (p = 0.424), respectively, for 16G and 18G needle study groups. The risk to undergrade a biopsy GS=6 was 21.1% and 15.4% (p = 0.709) using a 16G and 18G needle, respectively. Age, prostate-specific antigen, prostate volume and needle calibre were not independently associated with a higher risk of GS discordance. Conclusions: Needle size does not affect the concordance between biopsy and pathological GS. Although GS is not the only way to determine treatment, it is still an unresolved urological issue. © 2013 Canadian Urological Association.