【慎防 HER2 陽性乳癌腦轉移 新一代治療現曙光】

乳癌在香港女性癌症中長居榜首，其中 HER2 陽性乳癌屬於相對較惡的乳癌，佔本港乳癌個案約 20%。^1,2 HER2 陽性乳癌有較高的機會復發及轉移³，病情來勢洶洶，但隨著現今醫學技術不斷進步，相關治療亦出現新曙光；臨床腫瘤科專科醫生更以病例實證，即使患者復發或出現腦轉移，透過新一代治療，依然有機會令癌腫瘤消除。

治癒率大幅提高 籲患者積極面對治療

臨床腫瘤科專科醫生張寬耀醫生表示，HER2 陽性乳癌一向惡性度較高，而且生長速度較快，通常是患者自己觸摸到、或醫生於身體檢查已觸摸到乳房有腫塊，發現患者乳房皮膚出現凹陷、變紅、變厚，出現鱗片狀變化；亦見過情況更嚴重的，出現腋下淋巴腫脹、有硬塊或淋巴結脹大，表皮潰爛等。^4-7 HER2 陽性乳癌患者亦較容易復發及擴散，當中以腦轉移風險為高。³ 張醫生指，早年曾有患者接受單標靶治療 HER2 陽性乳癌，痊癒 4 年後出現肝轉移，遂建議一同檢查腦部，卻被患者婉拒；治療 9 個月後患者肝轉移腫瘤已萎縮，卻透過檢查發現一如張醫生所料，出現腦部轉移，幸患者終接受醫生建議，及早檢查腦轉移風險。HER2 陽性乳癌有較高腦轉移風險，而腦轉移初期未必有任何徵狀，故此張醫生特別叮囑乳癌復發的患者切勿諱疾忌醫，應及早檢查腦部，如發現腦轉移亦能及早醫治。

醫學日漸進步 治療效果顯著

「自從標靶藥物面世後，能有效治療及控制癌症，HER2 陽性乳癌早期患者的治癒率，已跟一般乳癌患者沒太大分別，7年約 93%、10 年約 70-75%，即使患者已是第三期，治癒率也跟一般乳癌一樣，整體治癒率高達 80-85%。」⁸ 張醫生透露，乳癌治療包括：外科手術、放射治療（電療）、化學治療（化療）、荷爾蒙治療、標靶治療，與免疫治療；⁹ 醫生會根據乳癌的分期、腫瘤大小、患者的健康狀況及意願作考慮，從而決定採用怎樣的治療方案；⁹ 如 HER2 陽性乳癌患者已出現腦轉移，則視乎症狀的輕重，去決定治療方案：「如患者的症狀已很嚴重，半邊身無力、出現嚴重頭痛、嚴重水腫、就要作出相應治療，某些情況如嚴重水腫，已經將腦部壓至一邊，就必須以外科手術治療，紓緩腦內壓力；患者亦有機會需要進行放射治療，或可使用口服標靶藥物，加上化學治療與注射標靶藥物治療。」¹⁰

取替傳統藥物 新一代治療成患者佳音

張寬耀醫生指出，腦部的血腦屏障為先天保護機制，不僅細菌、病原體、毒性物質無法進入，而傳統標靶藥物屬大分子量，藥物特性令其無法通過血腦屏障，消滅腦部的癌細胞，因此難以達到控制及治療腦轉移的效果；^11-13 隨著醫學不斷進步，醫學界研發出小分子口服標靶藥，能突破血腦屏障到達腦部，減低腦轉移風險。¹⁴ 而新一代治療 HER2 的口服小分子標靶藥物，配合注射標靶治療及化療藥物，不單對治療HER2 陽性乳癌腦轉移甚有療效，臨床研究亦指出，其針對穩定性腦轉移和活動性腦轉移，均有顯著效果。¹⁴

復發腦轉移具風險 小分子標靶藥解窘境

此外，張醫生亦強調恆常檢查的重要性，如家族有成員曾患乳癌的女士，應定期到婦科、外科或普通科作臨床檢查，有需要亦可進行磁力共振檢查；¹⁵ 美國婦產科學會 The American Congress of Obstetricians and Gynecologists (ACOG)，建議女性從 40 歲起接受乳腺造影檢查，如有乳房硬塊也能及早發現。¹⁶

提高自我撿查意識 配合生活習慣防患未然

談到如何預防早期 HER2 陽性乳癌及防止病情惡化，張醫生指健康生活最重要。

●  保持健康體重：肥胖是乳癌高危因素之一，因此要避免過重，身體質量指數(BMI) 應維持少於 23。^17,18 如體重超標，可先透過飲食調整，再維持運動習慣。

●  注意健康飲食：多吃水果、蔬菜和其他植物性食物如全穀類和豆類。¹⁹ 地中海飲食主要側重於植物性食物，如水果、蔬菜、全穀物、豆類和堅果，並輔以特級初榨橄欖油和混合堅果，可減少女性患乳腺癌的風險。^20,21 少選擇高熱量食物如精製糖和動物脂肪，減少食用紅肉，均可減低風險。^19,22,23

●  規律運動：運動可促進血液循環、淋巴排毒、紓壓、控制體重，這些好處都有效幫助預防癌症；^23-25 研究顯示，即使每天只進行 30 分鐘的運動，對健康已有莫大裨益。如有需要，可分為三次，每次運動進行 10 分鐘。²⁶ 情況許可的話，每周至少進行 150 分鐘中等強度帶氧運動（如急步行、在平地或微斜的道路踏單車、乒乓球和排球等），或每周至少 75 分鐘的劇烈帶氧運動（如競走、緩步跑或跑步、登高、健身操等）。^27,28

●  戒煙戒酒：吸煙可引致多種癌症。²⁹ 電子煙同樣含尼古丁，致癌風險與吸食煙草無異。³⁰ 另外，世界衛生組織的國際癌症研究機構將酒精列為第一類致癌物質，與煙草同一類別。^31,32 即攝取酒精及煙草愈多，患乳癌的風險愈高。

▲ 臨床腫瘤科專科醫生張寬耀醫生

本專欄由MSD 全力支持　HK-TUC-00075 Nov/2023

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