Serum concentrations of flutamide and goserelin in a prostate cancer patient with obstructive nephropathy: a case report

Abstract

72歳男.頻尿を主訴に当科受診.初診時, 前立腺はリンゴ大, 石様硬で, 血中PSA値は73ng/ml(RIA)であった.腹部CT検査では腫大した傍大動脈リンパ節と両側水腎症を認め, 両側経皮的腎瘻造設と経直腸的前立腺針生検を施行した.診断は中分化型前立腺癌で, ただちにgoserelin, flutamide投与を開始し, Crとその血中濃度を経時的に測定した.血中goserelinは治療開始後14日目で9.6ng/mlと, 国内臨床試験データより高い値を示したが, 血中flutamideは400から470ng/mlであった

A 72-year-old man presented with pollakiuria and dysuria. His prostate was the size of an apple and hard on digital rectal examination and the serum prostate specific antigen (PSA) level was 73 ng/ml (RIA). Ultrasonography revealed bilateral hydronephrosis and the serum creatinine level was 13.2 mg/dl. CT scanning of the abdomen demonstrated swelling of paraaortic lymph nodes. Transrectal needle biopsy of the prostate gave a diagnosis of moderately differentiated adenocarcinoma. Accordingly, the final diagnosis was prostate cancer (cT3N4M1, stage D2). Immediately after bilateral percutaneous nephrostomy, treatment with an LH-RH agonist (goserelin) and flutamide was commenced. Serum creatinine was 6.6 mg/dl at the start of antiandrogen therapy and decreased to 1.8 mg/dl after 27 days. A 125 mg flutamide capsule was administered at 7 a.m., and blood samples were collected 4 hours later on days 1, 2, 3, 5, 6, 8, 12, 14, 17, 18 and 27. The OH-flutamide concentration was measured. There was no significant correlation between serum creatinine and the OH-flutamide concentration. After implantation of goserelin (3.6 mg depot), blood samples were obtained at 11 a.m. on days 8, 12, 14, 15 and 25. The serum goserelin level was measured. The serum goserelin level increased to a peak on day 14, as described previously, but the peak value of 9.63 ng/ml was higher than that reported before (mean +/- SD 2.848 +/- 0.199).