[Gleason scores of prostate needle biopsy specimens and of radical prostatectomy specimens, a comparative study].

Objective: To compare the Gleason scores of the prostate needle biopsy specimens with those of the radical prostatectomy specimens.

Methods: Gleason scoring was made on the needle biopsy specimens from 40 patients with prostate carcinoma and then on the radical prostatectomy specimens from the same patients. The Gleason scores of the two sets of matched specimens were compared.

Results: The Gleason scores were 2 approximately 9 (5.6 +/- 1.7) of the prostate needle biopsy specimens, significantly different from those of the radical prostatectomy specimens [4 approximately 10 (6.4 +/- 1.3), P < 0.05]. The Gleason scores coincided in 23 cases (57.5%) between the two groups. The Gleason scores of 15 needle biopsy specimens were significantly lower than those of the matched radical prostatectomy specimens with an underestimation rate of 37.5% and were higher in 2 needle biopsy specimens than in the matched radical prostatectomy specimens with an overestimation rate of 5.0%. The number of cases with the Gleason score < or = 6 in the needle biopsy group were 25, significantly less than that in the radical prostatectomy group (P < 0.01). The number of cases with the Gleason score > or = 7 in the needle biopsy group was 15, not significantly different from that in the prostatectomy group (P = 0.07).

Conclusion: Prostate needle biopsy under-grades the Gleason scores in comparison with radical prostatectomy. Measures should be adopted to avoid underestimation of the tumor grade.