研究背景：
臨床醫師運用抽血測量血清特異性攝護腺抗原 (Prostate-Specific antigen, PSA)及攝護腺肛門指診 (Digital Rectal Examination, DRE)篩檢攝護腺癌，對於上述兩種檢測若有任何一種出現異常，則該病患將接受經直腸超音波導引攝護腺切片。若切片結果為陰性的病患，而血清PSA持續異常，未來仍可能接受再次切片，但是目前除了血清PSA外，有其他PSA衍生數據來增加切片的陽性預測率。本研究即是收集過去接受再次切片的病人，利用統計方法回溯性探討何種PSA衍生數據是較佳的攝護腺癌預測因子。
材料與方法 :
本研究回溯性收集台中榮民總醫院從1999年至2008年間所有接受二次經直腸超音波導引攝護腺切片的病患，其中排除DRE異常及血清PSA大於10 ng/ml的病患，有212位病患被納入本研究，我們收集這212位病患的血清總PSA(total PSA, tPSA)自由型PSA(free PSA, fPSA)佔總PSA(tPSA)之比值(f/t PSA)，PSA密度(PSA density, PSAD)及PSA上升速度(PSA velocity, PSAV)，並利用反應者操作特徵曲線(Receiver Operating Characteristic Curve, ROC curve)，在比較上述各種PSA衍生數據的優劣，最後再次利用統計方法找出各種PSA衍生數據的最佳閾值。
結果 :
本研究納入之212位病患中，有26人接受再次切片後，診斷為攝護腺癌，而其餘的186人診斷為良性攝護腺增生。各種PSA衍生數據在反應者操作特徵曲線下的面積分別是tPSA為72.7%，f/t PSA為57.9%，PSAD為74.4%及PSAV為64.8%，以上結果反應PSAD優於f/t PSA，成為一個較佳的攝護腺預測因子。此外，當PSAD的閾值定在0.18 ng/ml/cc 的時候，預測攝護腺癌的特異度高達69%，且其敏感度為77%是可以接受的範圍。
結論 :
於再次攝護腺切片的病患中，PSAD的確優於f/t PSA，成為一個較佳的攝護腺癌預測因子，並且PSAD提供較高特異度以減少不必要的再次切片。

Purpose: The aim of our study was to identify the optimal predictor of prostate cancer among several prostate-specific antigen (PSA) derivatives in repeat prostate biopsy.
Methods: We retrospectively assessed the repeat prostate biopsy specimens, obtained between 1999 and 2008, of 212 patients with total PSA (tPSA) of 4-10 ng/ml and normal digital rectal examination (DRE). Using receiver operating characteristic (ROC) analysis, we assessed the predictive power of tPSA, percent free PSA (f/t PSA), PSA density (PSAD), and PSA velocity (PSAV) for detection of prostate cancer.
Results: Repeat prostate biopsy specimens were positive for prostate cancer in the case of 26 patients and negative in the case of 186 patients. The areas under the ROC curve for tPSA, f/tPSA, PSAD, and PSAV were 72.7%, 57.9%, 74.4%, and 64.8%, respectively. The ROC curve analysis revealed that PSAD was a better predictor of prostate cancer than f/t PSA. Moreover, when PSAD at an optimal cutoff of 0.18 ng/ml/cc was considered as the predictor, the detection of prostate cancer was found to have a high sensitivity and specificity ( 77% and 69%, respectively).
Conclusions: In repeat prostate biopsy, PSAD is superior to f/t PSA as a predictor of prostate cancer and by assessing this predictor, unnecessary repeat biopsy of patients with tPSA of 4-10 ng/ml can be avoided.

目錄
頁碼
第一章 緒論
第一節 引言------------------------------------------- 1
第二節 攝護腺癌之診斷--------------------------------- 2
第三節 再次切片病患之血清PSA衍生數據------------------ 3
第二章 研究對象與方法
第一節 研究對象--------------------------------------- 4
第二節 經直腸攝護腺超音波及切片----------------------- 5
第三節 血清PSA及其衍生數據---------------------------- 6
第四節 統計方法--------------------------------------- 7
第三章 結果
第一節 研究對象之基本資料與血清PSA值及其衍生數據 -- 8
第二節 利用血清PSA及其衍生數據對於再次切片病患攝護腺癌診斷的敏感度與特異度------------------------------------ 9
第三節 利用血清PSA及其衍生數據對再次切片病患攝護腺癌診斷的優劣------------------------------------------------ 10
第四節 血清PSA及其衍生數據運用於再次切片病患之最佳閾值-------------------------------------------------------- 11
第四章 討論
第一節 是否再次切片為攝護腺癌診斷常見的問題-------- 12
第二節 增加穿刺數目於再次切片的角色---------------- 13
第三節 運用各種PSA衍生數據減少不必要的再次切片----- 14
第四節 ROC曲線上找出最佳閾值----------------------- 17
第五節 結論與建議---------------------------------- 18
參考文獻---------------------------------------------- 19
附件
表一-------------------------------------------------- 22
表二---------------------------------------------- 23
表三---------------------------------------------- 24
圖一---------------------------------------------- 25

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