乳癌的標靶治療

本文的討論將以已上市或是即將上市的乳癌標靶藥物為主。目前乳癌已獲FDA 或是歐盟許可上市的主要的標靶藥物依作用途徑不同可分為三類：第二型人類上皮細胞生長因子接受器（HER2）抑制劑，血管新生抑制劑，及mTOR 抑制劑。HER2 陽性的轉移性乳癌病人接受化療的療效較HER2 陰性的乳癌病人差，存活期較短。HER2 陽性的早期乳癌病人轉移復發率較高，存活率較低，接受輔助性化療的成效也較差。自從針對HER2 受體的標靶藥物trastuzumab 上市之後，目前HER2 陽性的病人（不論是早期乳癌還是轉移性乳癌）反而變成預後較好的族群了。目前和未來臨床上還有許多新的HER2 抑制劑可使用。血管新生抑制劑合併化學治療在轉移性乳癌患者中能增加化學治療的腫瘤反應率及無疾病惡化存活期。mTOR 抑制劑合併荷爾蒙治療在荷爾蒙受體陽性的患者也展現了顯著的臨床治療效果。

Optimizing breast cancer therapy to increase cure rates in early stage disease and improve life expectancy and palliation for patients with metastasis is a critical need and major area of research in medical oncology. This article focuses on the clinical available targeted therapy in breast cancer. According to the difference in mechanisms, these targeted therapies could be divided into three groups, including HER2 inhibitor, anti-angiogenic therapy, and mTOR inhibitor. For HER2-positive breast cancer patients, anti-HER 2 therapy has several new drugs available. The first drug approved is trastuzumab, which has been proven to improve response rate, progression free survival and overall survival in metastatic disease, and improve disease recurrence free survival and overall survival in early breast cancer. Other promising agents include lapatinib, pertuzumab, and trastuzumab emtansine. Combination of anti-angiogenic therapy agent, bevacizumab, with chemotherapeutic agent, has been proven to improve response rate and progression free survival in metastatic breast cancer. Combination of mTOR inhibitor (everolimus) with hormonal therapy has been proven to improve response rate and progression free survival for estrogen receptor-positive breast cancer patients who are refractory to at least one line of hormonal therapy. Topics reviewed in this review include the mechanisms of these targeted therapeutic agents, target population, important clinical trial results, and the status of reimbursement of National Health Insurance.