目的：為了評估血中前列腺特異抗原在轉移前列腺癌患者接受男性荷爾蒙去除療法後的預後意義。材料及方法：在三十九個有轉移的前列腺癌接受男性荷爾蒙去除療法的病人，我們收集並分析六個治療前的臨床病理因子及五個治療後前列腺特異抗原變化的指數。這些病人年齡從五十歲到八十四歲（平均六十七點八歲），定期追蹤從十二個月到九十六個月（平均二十七點九月）。結果：單變項數分析顯示(l)病人年齡大於六十五歲，(2)三個月內前列腺特異抗原回歸正常（小等於4ng/ml）,(3)前列腺特異抗原最低值小於1ng/ml，及(4)前列腺特異抗原維持正常時間大於十二個月是四個有意義的預後指標(p<0.05)；然而，治療前的前列腺特異抗原值、前列腺特異抗原半衰期及加倍期則不是有意義的指標。利用Cox氏多變項數分析顯示前列腺特異抗原維持正常時間大於十二個月是最強的指標。再者，有前列腺特異抗原最低值小於1.0ng/ml的病人會比最低值藉於1到4ng/ml的病人有較長的維持正常值的時間，但兩者的前列腺特異抗原加倍期則無差別。結論：本研究結果顯示(l)病人年齡大於六十五歲，(2)三個月內前列腺特異抗原回歸正常，(3)前列腺特異抗原最低值小於1ng/ml，及(4)前列腺特異抗原維持正常時問大於十二個月是有轉移的前列腺癌接受男性荷爾蒙去除療法的病人四個有意義的預後指標。通常，治療後病人的前列腺特異抗原最低值愈低的話，其前列腺特異抗原維持正常時間會愈久，病人的預候也會愈好。

Objective: To evaluate the prognostic value of changes in prostate-specific antigen (PSA) on the outcome of patients with metastatic prostate cancer treated with androgen ablation. Patients and Methods: We analyzed 6 pretreatment clinicopathological and 5 posttreatment PSA parameters in 39 advanced prostate cancer patients receiving androgen ablation. Their ages ranged from 50 to 84 (mean, 67.8) years, and they were regularly followed up for 12 to 96 (mean, 27.9) months. Results: Univariate analysis revealed that (1) a patient's age of >65 years, (2) a PSA drop to ≤4ng/ml within 3 months (i.e., a return to normal), (3) a PSA nadir value of <1ng/ml, and (4) a duration of PSA of ≤4ng/ml of longer than 12 months were 4 significant prognostic indicators for the disease-specific overall survival (p<0.05), whereas the pretreatment PSA value, PSA half-life, and PSA doubling time were not. Further analysis with the multivariate Cox proportional hazard models revealed that a duration of PSA normalization of longer than 12 months was the strongest indicator of a favorable outcome. Moreover, patients with a PSA nadir value of <1ng/ml had significant longer normalization periods but not PSA doubling times compared to those who had a PSA nadir value of between 1 and 4ng/ml. Conclusions: Results of this study reveal that (1) an age of ≥65 years, (2) a drop in the PSA value to ≤4ng/ml within 3 months, (3) a PSA nadir value of <1ng/ml, and (4) a PSA normalization duration of >12 months were the 4 significant prognostic parameters of metstatic prostate cancer patients treated with androgen ablation. In general, the lower the PSA nadir value a patient is able to achieve the longer the PSA normalization period and eventually a better disease-specific survival he may enjoy.