Does extended prostate needle biopsy improve the concordance of Gleason scores between biopsy and prostatectomy in the Taiwanese population?

Abstract

Background: Discordance between the Gleason scores of prostate needle biopsies and radical prostatectomy specimens has been reported by several investigators. We conducted this study to determine if increasing the number of prostate needle biopsies in patients with prostate cancer improves the accuracy of Gleason scores in the Taiwanese population.

Methods: Between March 2000 and September 2009, 281 patients underwent radical prostatectomy at Taipei Veterans General Hospital. All of these patients had prostate cancer that was diagnosed and graded either by extended needle biopsy (121 patients, ≥ 10 cores/patient, range: 10-13, median: 12) or by traditional sextant transrectal biopsy (160 patients, <10 cores/patient, range: 6-9, median: 6). We analyzed the patients' Gleason scores of their biopsies and radical prostatectomy specimens.

Results: The concordance rate, defined as similarity between the Gleason score of a patient's biopsy and prostatectomy specimens, was 57.9% in the extended biopsy group and 45.6% in the nonextended biopsy group (χ(2) test: p = 0.042). The primary Gleason pattern was accurately predicted by extended needle biopsy in 81% of cases (98/121 cases), higher than the 70% accuracy rate of the nonextended biopsies (112/160 cases, p = 0.036). Undergrading was found in 43/121 cases (32%) and 63/160 cases (39.4%) (p = 0.511). However, overgrading was found in 8/121 cases (6.6%) and in 24/160 cases (15.0%) (p = 0.028) by extended and nonextended biopsies, respectively. Forty-seven (16.7%) of those patients who fit the criteria of active surveillance were upgraded to a Gleason score >7 after radical prostatectomy.

Conclusion: The addition of an extended transrectal needle biopsy increases the accuracy of the Gleason score for predicting the final prostate cancer grade in the Taiwanese population.