経尿道的前立腺切除後に発生した前立腺導管癌の1例

Abstract

66歳男。人間ドックで血清前立腺特異抗原異常高値, 排尿困難を訴え, 経尿道的前立腺切除術を行った。1年後PSAが低下後, 徐々に上昇したため再生検を勧めたが患者の同意を得られずPSAが13.2ng/mlになった時点で同意した。根治的前立腺全摘術を施行し, 病理所見は中分化癌で被膜浸潤はなく, 切除断端陰性であった。術後PSAが2.5ng/mlまでしか低下せず, 遠隔転移, 局所腫瘍残存を考えた。CT, MRI, 骨シンチを施行したが明らかな遠隔転移, 局所再発は認めなかった。病理組織を再検したところ尖部右側に充実胞巣状増殖を主体として, 少量の腺癌部分を混在する導管癌を認め, MAB療法, DES-DP大量療法を施行した。

A 66-year-old man visited our hospital complaining of a high prostate-specific antigen (PSA) (6.9 ng/ml) and dysuria. Prostatic needle biopsies revealed no malignancy in January 1998 and February 1999 (PSA 8.0 ng/ml). Transurethral resection of prostate (TURP) was performed in March 1999. Although none of the TURP specimen showed any malignancy, the PSA level remained high (3.7 ng/ml 1 year after the TURP), and gradually increased. About 3 years later, re-biopsy was done (PSA 13.2 ng/ml) and pathological finding was moderately differentiated adenocarcinoma (Gleason score 3 + 3 = 6). After 9-month MAB, radical prostatectomy (RP) was performed in January 2003 (PSA 4.2 ng/ml). Though the RP specimen showed moderately differentiated adenocarcinoma with negative capsule penetration and negative surgical margins, PSA decreased to 2.5 ng/ml and gradually increased. Computed tomography (CT), magnetic resonance imaging (MRI), and bone scintigraphy showed neither distant metastasis nor local recurrence. Review of the RP specimen revealed ductal carcinoma with positive capsular penetration and suspicion of positive surgical margins. Although the patient was treated with maximum androgen blockade, diethylstilbestrol diphosphate, and tegafururacil, PSA gradually increased and was kept at a high level (5-6 ng/ml). In December 2005, the patient complained of anal pain and MRI showed a 4.8 x 2.3 cm tumor in the prostatic bed. Needle biopsy of the tumor revealed ductal carcinoma (PSA 6.39 ng/ml). In January 2006 (PSA 11.9 ng/ml), we initiated a treatment with 66 Gy of intensity modulated radiation therapy. In November 2006, PSA decreased to 0.279 ng/ml, and the tumor reduced (3.8 x 1.0 cm) on MRI.