Active surveillanceの適応と考えられた前立腺全摘症例の検討

Abstract

To develop a more clinically relevant protocol and identify the best candidates for active surveillance (AS), we examined the pathological features of radical prostatectomy (RP) specimens of patients who met the Japanese AS protocol criteria. Of 342 patients who underwent RP between 2000 and 2010, 58 (17.0%) eligible for the Japanese AS protocol were retrospectively identified. Pathological features of biopsy specimens and RP specimens were compared to reveal the incidences of up-grading, up-staging and insignificant cancer. We also tried to identify preoperative clinical and pathological factors that accurately predicted the insignificant cancer in the surgical specimens. Up-grading (Gleason score ≥7) and upstaging (≥pT3) were observed in 32 (55.2%) and 6 (10.3%) patients, respectively. Insignificant cancer was observed in 19 (32.8%). Dominant tumors were located in the peripheral zone (PZ) in 34 (58.6%) patients and in the transition zone (TZ) in 24 (41.4%). Multivariate analysis revealed that prostate-specific antigen density ＜0.15 ng/ml/cm3 was a significant independent factor to predict insignificant cancer (odds ratio 6.70, p＝0.036). Larger dominant tumors were associated more frequently with up-grading and up-staging (p＝0.038 and p＝0.021, respectively), and were more likely to be located in the TZ (P＝0.027). Our results suggest that the risk of up-grading and up-staging should be considered in patients who met the Japanese protocol. Larger dominant tumors were associated more frequently with up-grading and up-staging.