乳癌的荷爾蒙治療

乳癌的荷爾蒙治療是癌症最早的特異性冶療（標靶治療）。荷爾蒙冶療的作用機轉簡單的說就是阻斷動情激素對乳腺細胞的作用，可作用在細胞內的動情激素受體上或是直接抑制動情激素的合成，泰莫西芬（tamoxifen）及氟維司群（faslodex）的作用機轉屬於前者，而停經後婦女使用的芳香環酶抑制劑（aromatase inhibitor）及停經前婦女使用的黃體∕濾泡激素抑制劑（LH/FSH inhibitor）的運作方式則屬於後者。目前對泰莫西芬（tamoxifen）的使用年限，根據ATLAS研究的建議，已由5年延長為10年；然而，對於高復發風險的停經後婦女，直接使用芳香環酶抑制劑則是較佳的選擇，但使用二到三年的泰莫西芬或五年的泰莫西芬再接續使用芳香環酶抑制劑也是可行的方案；此外，對於停經前的婦女，可使用黃體∕濾泡激素抑制劑（LH/FSH inhibitor）來加強泰莫西芬的療效或可取代第一代的化學治療；氟維司群則可用於停經後婦女的轉移性乳癌的較後線治療。對於荷爾蒙受體陽性的轉移性乳癌，最新研究顯示：抗藥性的產生很有可能是來自mTOR訊息傳遞路徑的活化。併用雷帕霉素靶蛋白抑制劑（mTOR inhibitor）如癌伏妥（everolimus）及芳香環酶抑制劑可能是未來轉移性乳癌病患新的治療選擇。

Hormone therapy in breast cancer is the first cancer target therapy. The goal of hormonal treatment is to block the effects of estrogen: either by interfering with the estrogen-receptor interaction, such as tamoxifen (Tamoxifen) and fulvestrant (Faslodex), or by directly inhibiting the synthesis of estrogen, such as aromatase inhibitors(anastrazole, letrazole and exemestane ) for postmenopausal women and luteal / follicular hormone inhibitors (LH / FSH inhibitor) for premenopausal women. According to the study's recommendations from ATLAS trail recently, continuing tamoxifen for 10 years rather than stopping at 5 years produces a further reduction in recurrence and mortality, particularly after year 10. For high risk postmenopausal patients, upfront usage of aromatase inhibitors and a switch in prescription after two to three years of tamoxifen, or 5 years in cases of extended treatment, are recommended options. LH / FSH inhibitors for premenopausal women can strengthen the efficacy of tamoxifen or replace the first generation of chemotherapy. Fulvestrant (Faslodex) can be used for postmenopausal women with metastatic breast cancer. For hormone receptor-positive metastatic breast cancer, drug resistance is likely derived from the activation of the mTOR signaling pathway. mTOR inhibitors such as Everolimus combined with aromatic inhibitors may be a new treatment option in the future.