前立腺癌に対するPSA低値で再開する間欠的内分泌療法の成績: 初回休薬期間の検討を中心に

Abstract

PSAが2ng/ml以上で内分泌療法再開, 0.3ng/ml以下で休薬という新しいプロトコールで間欠的内分泌療法を32例の前立腺癌患者に対して施行したので, その短期成績を報告した.初回休薬期間の中央値は287日と満足のいくものであった.初回治療期間とテストステロン値の回復には負の相関を認め, 初回治療期間が長期であればテストステロン抑制は休薬しても長期持続することが示された.長期に亘る視床下部-下垂体-精巣ホルモン軸の抑制は精巣機能の障害を長期化し, 間欠的内分泌療法に必要なテストステロン値の回復を遅らせるかもしれない

We report a pilot study on a novel protocol of intermittent androgen deprivation (IAD) treatment of prostate cancer (PC), in which androgen deprivation is restarted when serum prostatic specific antigen (PSA) level reached more than 2 ng/ml and is stopped when PSA level decreased below 0.3 ng/ml. Thirty-two patients (aged 60 to 86 years, median 74 years) with prostate cancer (Stage A in 4 patients, B in 20, C in 1, D in 5, and relapse after radical prostatectomy in 2) were treated with IAD. Median serum PSA prior to the start of endocrine therapy was 15.65 (range 2.67 to 306.3) ng/ml. Eleven patients were treated with lutenizing-hormone-releasing hormone (LHRH) agonist alone and 21 were treated with LHRH agonist plus an antiandrogen. Median duration of first endocrine therapy was 572 (range 100 to 1, 543) days. Median serum PSA at the start of first off-phase was 0.038 (range 0.003 to 0.489) ng/ml. After a median of 207 days (range 140 to 843) of follow-up, 19 patients were in the first cycle, 9 in the second cycle, 3 in the third cycle, 1 in the fourth cycle. Two patients developed androgen-independent PC. The median duration of first off-phase of IAD was 287 days. There was a significant inverse relation between the duration of the first on-phase and testosterone level measured 4 months after the cessation of first on-phase therapy (R = -0.518). These results suggest that our protocol provides a reasonable length of off-phase duration and that the long term-androgen deprivation phase might delay the recovery of the testicular endocrine function which should be maintained during the off-phase of IAD.