Intermittent androgen deprivation therapy may prolong the duration of androgen dependence of well-differentiated prostate cancer

Abstract

われわれは過去にPSAが0.3ng/ml以下になれば休薬し2.0ng/ml以上になれば再開する方法で行った前立腺癌に対する間欠的内分泌療法の成績を発表した.今回は間欠療法と通常療法で内分泌不応性となるまでの期間を比較した.1995～2003年の間に限局性, 転移性前立腺癌と診断された患者および根治的前立腺全摘出後に生化学的再発をきたした46人の患者を間欠的内分泌療法で治療した.この中で間欠的内分泌療法の第2サイクル以降に入った患者(30人)を研究対象にし, 通常療法を受けPSAの底値が0.3ng/ml以下になった患者33人をコントロールとした.間欠療法, 通常療法の5年間生化学的非再発率はそれぞれ59%および89%で有意差はなかった(p=0.5).高分化型前立腺癌に対しては間欠療法が, 中低分化型に対しては通常療法が有意に5年間生化学的非再発率が高い結果となった.これらの結果より高分化型前立腺癌に対して間欠的内分泌療法は通常の方法よりも有効な治療法であることが示唆された(著者抄録)

We previously reported the results of a pilot study of intermittent androgen deprivation (IAD) therapy in which surveillance was performed when PSA level fell below 0.3 ng/ml and androgen deprivation was resumed when PSA level exceeded 2.0 ng/ml. In the present study, we compared the duration of androgen dependence in patients treated with IAD with that in patients with continuous androgen deprivation (CAD) therapy. Forty-six patients with clinically localized or metastatic prostate cancer, or biochemical recurrence after radical prostatectomy were treated with IAD from 1995 to 2003. Patients in or after the second cycle of IAD (30 patients) were evaluated for duration of androgen dependence. Patients whose serum PSA nadir became <0.3 ng/ml (33 patients) represented a control group of CAD. The overall 5-year biochemical progression-free rate was 58% and 89% in the IAD and CAD groups, respectively; there was no significant difference between the two groups (p=0.5). Subgroup analysis showed that, irrespective of metastasis, the 5-year biochemical progression-free survival rate in the IAD group was not significantly different from that in the CAD group. However, IAD offered significantly better results for well-differentiated prostate cancer, whereas CAD offered significantly better results for moderately or poorly differentiated prostate cancer. The results obtained from this retrospective and nonrandomized study suggested that IAD may be a feasible treatment for well-differentiated prostate cancer.