Gleason score and laterality concordance between prostate biopsy and prostatectomy specimens

ABSTRACT

Objectives: Prostate biopsy involvement and Gleason score guide treatment decisions in prostate cancer. We evaluated concordance in Gleason score and laterality between biopsy and radical retropubic prostatectomy (RRP) specimens and factors that influenced this relationship. Material and Methods: We reviewed 538 prostate cancer diagnoses at a Veterans Affairs medical center (2000-2005) to identify men with prostate biopsy and RRP specimens. During this time there was a move from limited (6 core) to extended (12 core) biopsy schemes. Discordance in Gleason score was defined as any change in Gleason score. Results: 152 men underwent RRP with biopsy showing Gleason < 7 in 56 percent, 7 in 36 percent, and > 7 in 8 percent. Biopsy involvement was unilateral in 59 percent and bilateral in 41 percent. Compared to the biopsy, RRP Gleason score was concordant in 76 (50 percent), higher in 51 (34 percent), and lower in 25 (16 percent). Bilateral involvement was concordant in 97 percent, while unilateral involvement was concordant in only 20 percent. Both Gleason score and laterality were concordant in only 26 percent. Gleason concordance was higher in those with 8 or more cores compared to < 8 cores taken (54 percent vs. 34 percent, p = 0.046), but concordance was not affected by age, PSA, prostate volume, or length of time from biopsy to RRP. During later years, concordance did not improve despite taking more cores. Conclusions: Prostate biopsy underestimated prostatectomy Gleason score in 34 percent of men and bilateral involvement in 80 percent of those with unilateral disease on biopsy. Taking at least eight cores improves the accuracy of the prostate biopsy.