Discrepancy between Gleason score of needle biopsies and radical prostatectomy specimens: current situation of general pathologists

岐阜大学及びその関連施設での前立腺針生検標本と全摘標本のグリソンスコア(GS)の一致率や, 一致率に影響を及ぼす因子について, 泌尿器病理が専門でない一般病理医の現状で検討した。153例を対象に検討した結果, 生検標本と全摘標本のGSの一致率は49.7%であった。生検でGSが4以下と診断された症例が11.1%あり, 一般病理医間でGSが正しく認識されていない可能性が示唆された。生検標本でGSが6の症例では, 全摘標本では7になる傾向があった。生検標本で%陽性コアが高い症例は, 全摘でGSとの一致率が高い傾向を認めた。一致症例は不一致症例に比べて生検本数が有意に多かった。%陽性コアが25%以上の症例では, 有意に過小評価が少なく, 一致率が高い傾向にあった。生検でのGSが6で過小評価されていた症例では, 被膜外浸潤陽性例が有意に多かった。生検でのprimary gradeが3以下で, PSAが10ng/ml以上の場合, 有意に全摘でのprimary gradeがupgradeした症例が多く, PSA値は重要な判断基準となると考えられた。
We retrospectively reviewed the discrepancy in Gleason score between needle biopsy and radical prostatectomy specimens. Specimens from 153 patients who underwent radical retropubic prostatectomy at Gifu University Hospital and 9 community-based institutions between January 2001 and December 2005, were studied. Gleason score was determined by the general pathologist at each institution. The coincidence rate of Gleason score between biopsy and prostatectomy specimens was 49.7%. In contrast, 37.4% of biopsy specimens were undergraded. In biopsy specimens given a Gleason score of 5 or less, the Gleason score was coincident or undergraded compared with prostatectomy specimens. In biopsy specimens given a Gleason score of 6, the coincidence rate was 39.6%. In 56% in biopsy specimens of cancers with a Gleason score of 6 the Gleason score was undergraded compared with the prostatectomy specimen. In this group, extra-prostatic extention was found significantly more often than in other groups (p = 0.04). In patients, who underwent extended biopsy, or had a more positive biopsy core (> or = 25%), the coincidence rate was significantly greater (p = 0.03). We should be aware of the limitations of Gleason scores based on biopsy specimens, and give treatment opinions careful consideration.