為了了解在經尿道前列腺切除術後須多長期間，手術引起的前列腺特異抗原值上升，才能回復到正常值或穩定值。我們設計了一個臨床研究計劃，共選取24名前列腺肥大接受經尿道前列腺切除術的病人，分別於手術前及手術後24小時，7日、14日及28日測量其血清之前最腺特異抗原值。以統計方法分析結果，我們可發現前列腺特異抗原值在手術9.9日回復到手術前之數值。以4.0ng/ml為正常值上限，則在手術後21.7日回復到正常值。而手術後第三週時前列腺特異抗原值回到穩定之狀態。有了這些參考日數後，吾人才能知道手術後多久之前列腺特異抗原值是否資憑斷的。

A clinical study was designed to determine the duration required for serum prostatespecific antigen (PSA) concentration return to a stable value following transurethral resection of the prostate (TUR-P). There were 24 patients in study. The serum PSA concentrations were measured before the procedures, then 24 hours, 1 week, 2 weeks and 1 month following TUR-P. Using statistical analysis, it was found that the PSA value returned to pre-operative level at 9.9 days. The upper limit of PSA value of normal range is defined as 4.0ng/ml; the PSA value returned to this value at 21.7 days after TUR-P. Also the PSA value will return to stable baseline level the third week , post-operatively. The physician should thus wait at least three weeks after TUR-P for PSA to reach, baseline levels.