[Comparisons of histological grading between biopsy and radical prostatectomy specimens in prostatic adenocarcinoma]

To examine how accurately biopsy specimens reflect the corresponding excised specimens in terms of histologic grades of prostatic adenocarcinoma, histologic grades of biopsy specimens were compared to those of radical prostatectomy specimen in 29 patients who underwent radical prostatectomy without any prior treatment.

For the assessment of histological grading, Japanese General Rule for Prostatic Cancer (JGRPC), in which adenocarcinoma was graded as being either well, moderately or poorly differentiated, and Gleason's system were applied.

According to JGRPC, histologic grades of biopsy specimens were identical to those of the prostatectomy specimens in 83% of cases, with biopsy specimens given higher grades than those of the prostatectomy specimen in 4 (14%), and lower grades in 1 (3%). According to Gleason score histological grade of biopsy specimens were identical to those of the prostatectomy specimens in only 52%. However, the grouping category of Gleason score (2 to 5, 6, 7 and 8 to 10) assigned to the biopsy was lower than that of prostatectomy specimen in only 3 cases (10%) and was greater than that of prostatectomy specimen in 5 cases (17%).

These results suggest that histological grades based upon biopsy specimens will predict those of the corresponding prostatectomy specimens in the majority (72% to 83%) but not all of the cases.