周易 呂世杰 王蘭君 范麗昕#
1大連市第三人民醫院腫瘤內科,大連 116031
2大連市婦產醫院婦產科,大連 116033
3大連市友誼醫院神經內科,大連 116100
胃癌HER-2表達與術后輔助化療療效的相關性分析
周易1呂世杰2王蘭君3范麗昕1#
1大連市第三人民醫院腫瘤內科,大連116031
2大連市婦產醫院婦產科,大連116033
3大連市友誼醫院神經內科,大連116100
目的通過總結胃癌術后輔助化療病例及HER-2表達情況,探討HER-2表達與胃癌術后輔助化療療效之間的相關性。方法回顧性分析185例胃癌術后輔助化療患者資料,總結其病理特點、HER-2表達狀況及無疾病進展生存(DFS)、總生存(OS),分析HER-2與臨床病理特點及DFS、OS的關系。結果185例胃癌患者中,HER-2陰性141例,陽性44例,陽性率24%。HER-2基因的擴增與腫瘤部位、腫瘤的分化程度及遠處轉移部位相關,與年齡、性別、分期無關;HER-2陽性組中位DFS為9.1個月,中位OS為15.1個月,HER-2陰性組中位DFS為15.2個月,中位OS為25.5個月,HER-2陰性的患者較HER-2陽性的患者更能從術后輔助化療中獲益(P=0.046),并且生存期更長(P=0.01)。結論HER-2無擴增的患者可從術后輔助治療中獲益,DFS與OS均有延長。
胃癌;術后輔助化療;HER-2;無疾病進展生存
Oncol Prog,2016,14(3)
胃癌是威脅人類健康的惡性腫瘤之一,其發病率及病死率居惡性腫瘤第2位[1-4],其治療方法主要為手術治療。然而,單純手術一般僅對于早期患者是根治性的,對于進展期可切除的患者,生存率仍較低。圍手術期和輔助治療方法為患者帶來了不同程度的臨床獲益,但沒有標準治療方法[5-7]。胃癌分子病因學的研究進展促進了靶向治療的研究。其中一個靶點是人表皮生長因子受體2(HER-2)膜受體,它在乳腺癌[8]、卵巢癌[9-10]、子宮內膜癌[11]和唾液腺癌[12]中是一個預后不良的標志物。在胃癌中,已報道的通過熒光原位雜交法(FISH)檢測的HER-2基因擴增率及通過免疫組化(IHC)檢測的蛋白過表達率范圍很大,為5%~53%[13]。有關胃癌中HER-2的預后預測價值的報道仍存在爭議[14-18]。一項國際多中心隨機對照Ⅲ期臨床研究(ToGA試驗)的結果顯示在胃癌中HER-2是臨床上一個重要的藥物靶點,但關于HER-2作為一個在沒有系統治療的情況下的預后標志物的價值尚未達成共識,同樣關于HER-2是否可作為系統治療的療效預測標志物也尚無一致結論。本文通過回顧性分析大連市第三人民醫院2003—2013年收治的胃癌術后輔助化療患者共185例,來探討HER-2基因表達與胃癌術后輔助化療療效及總生存的關系。
1.1研究對象
選取我院2003—2013年收治的胃癌患者病例211例,所有患者均于我院行胃癌根治術,手術病理證實,經免疫組化或FISH檢測明確HER-2基因狀態,術后3個月內行輔助化療,至少4周期。其中隨訪資料不足,HER-2基因不明確,分期為Ⅰ期未行術后輔助化療及化療周期數不足4周期病例26例,可用病例185例。其中男性102例,女性83例;年齡22~81歲;術后分期:Ⅱ期54例,Ⅲ期131例;腫瘤部位:胃食管結合部70例,胃體37例,胃竇78例;分化程度:低分化88例,中分化27例,高分化4例,印戒及黏液腺癌66例。化療方案包括氟尿嘧啶聯合順鉑(FP),奧沙利鉑聯合卡培他濱(XELOX),奧沙利鉑聯合氟尿嘧啶、亞葉酸鈣(FOLFOX4、FOLFOX6),表阿霉素聯合氟尿嘧啶、順鉑(ECF)以及氟尿嘧啶衍生物的單藥治療。
1.2HER-2結果判定
1.2.1免疫組化法檢測手術標本HER-2評分根據胃癌HER-2檢測指南[19]:①0:無反應或小于10%的腫瘤細胞染色;②(+):≥10%的腫瘤細胞微弱或隱約可見膜染色,僅有部分細胞膜染色;③(++):≥10%的腫瘤細胞有較弱至中度的基底側膜、側膜或完全性膜染色;④(+++):≥10%的腫瘤細胞基底側膜、側膜或完全性膜強染色。0及(+)的病例判斷為HER-2陰性,(+++)的病例判斷為HER-2陽性,(++)的病例判斷為不確定,需進一步行FISH檢測,如FISH檢測陽性,判斷為HER-2陽性,如FISH檢測陰性則判斷為HER-2陰性。
1.2.2FISH檢測HER-2基因擴增判讀方法參照ToGA研究經驗[20]。觀察時避免計數重疊的細胞核、分裂期的細胞核或被截斷的細胞核,避免計數不顯示任何信號的細胞核和僅顯示一種顏色信號的細胞核。選擇擴增程度最高的區域,至少20個連續腫瘤細胞核進行雙色信號的計數和比值計算,HER-2信號總數與CEP17信號總數的比值≥2.2,判斷為原位雜交陽性,即有擴增;眾多信號連接成簇或HER-2與CEP17信號比值>20時可不計算比值,判斷為原位雜交陽性;HER-2信號總數與CEP17信號總數的比值<1.8,判斷為原位雜交陰性,即無擴增。HER-2與CEP17信號比值為1.8~2.2時,再計數20個細胞的信號或由另一位醫師計數,若比值≥2.0判斷為原位雜交陽性,比值<2.0判斷為原位雜交陰性。
1.3隨訪
所有患者治療結束后每3個月隨訪一次,直至病情進展或死亡。隨訪內容包括癥狀、體征、肝腎功能及采用超聲、CT以及MRI、ECT、PET-CT等評價患者是否出現復發轉移。
1.4統計學方法
采用SPSS 18.0統計軟件進行統計分析,將所有數據錄入數據庫,計數資料采用χ2檢驗,并采用Kaplan-Meier生存曲線進行統計分析,P<0.05為差異有統計學意義。
2.1HER-2在胃癌中的表達與臨床特征的關系
185例胃癌患者中,HER-2陰性141例,陽性44例,陽性率24%。HER-2基因的擴增與腫瘤原發部位、腫瘤的分化程度及復發轉移的部位相關,差異有統計學意義(P<0.05),與年齡、性別、分期無關,差異無統計學意義(P>0.05)。(表1)

表1 胃癌患者手術標本HER-2表達與患者臨床特征的關系
2.2HER-2表達與術后輔助化療療效的相關性
HER-2陽性組中位無疾病進展生存(disease free survival,DFS)為9.1個月,明顯短于HER-2陰性組的15.2個月,兩組差異具有統計學意義(P=0.046),見圖1。
2.3HER-2表達與總生存(over survival,OS)的相關性
HER-2陽性組中位OS為15.1個月,明顯短于HER-2陰性組的25.5個月,兩組差異具有統計學意義(P=0.01),見圖2。

圖1 HER-2表達情況與DFS的生存曲線

圖2 HER-2表達情況與OS的生存曲線
胃癌是我國常見的消化道惡性腫瘤之一,其病死率位于惡性腫瘤的第2位[1-4]。HER-2基因的擴增與胃癌的發生發展密切相關。HER-2基因是HER家族的一員,HER-2蛋白的過表達或者基因的擴增被認為是促進腫瘤發展的重要因素。HER-2的突變可激活HER-2基因,使多種細胞發生惡性轉化或增加其惡性程度。HER-2的突變多在外顯子20,Wang等[21]認為,HER-2的突變包含1個G776插入到外顯子20,突變體HER-2比野生型HER-2能更有效地激活信號轉導、磷酸化表皮生長因子受體(EGFR)、誘導腫瘤的形成和擴散。據報道,10%~34%的侵襲性乳腺癌中存在HER-2蛋白的過表達和(或)HER-2基因的過度擴增,且HER-2蛋白的過表達與乳腺癌患者的不良預后有關[22]。此外HER-2蛋白的過表達可能是導致化療和內分泌治療乳腺癌不敏感的潛在因素。HER-2除了在乳腺癌中存在過表達外,在食管癌、胃癌、結直腸癌、肺腺癌等多種癌組織中均發現HER-2的過表達[23-26]。
研究報道胃癌的HER-2蛋白陽性過表達率為8.2%~45%[27],本研究結果HER-2陽性表達率為24%,與相關的研究結果相符合。相關臨床病理結果顯示HER-2的表達與腫瘤的部位、分化程度、分期及遠處轉移相關,HER-2陽性患者胃癌發生部位以近端胃為主(48%),分化程度多為中高分化及低分化(分別為34%及36%),遠處轉移以肝臟及其他遠處轉移為主(分別為47%及77%)。HER-2陰性患者腫瘤發生部位以遠端胃為主(48%),印戒及黏液腺癌所占比例較高(38%),轉移部位多為腹膜及淋巴結(分別為78%及84%)。HER-2的表達與年齡、性別、分期無關,這與相關研究相一致[28-31],但也有些報道不相符,可能為樣本量較小以及均為術后輔助治療病理而造成的偏倚,有待進一步的驗證。關于HER-2表達與預后的關系,本研究顯示HER-2表達與患者預后相關,HER-2陰性患者DFS延長(P=0.046),OS延長(P=0.01),更能從輔助化療中獲益。這一結論國內外報道仍有爭議,可能與化療方案的不同相關,多位學者報道HER-2并非胃癌獨立的不良預后因素[32-41]。但Gordon等[42]報道稱HER-2的表達與胃癌術后輔助化療的獲益相關,HER-2陰性的患者更能從術后輔助化療中獲益,包括DFS與OS,這與本文的結論相一致。因目前類似報道仍較少,且本研究樣本量較少,需進一步深入研究。
胃癌的發生、發展過程復雜,與癌基因的激活、抑癌基因的失活相關,尋找與胃癌發生、發展及預后相關的生物學指標,檢測癌基因及抑癌基因的表達產物對胃癌的影響,有助于胃癌的早期發現及診斷,并為胃癌的靶向治療提供方向。HER-2是促進胃癌發生發展的重要因素之一,評估HER-2與胃癌發生的作用機制以及相關臨床治療需要進一步的深入研究。針對HER-2過表達的相關分子靶向藥物曲妥珠單抗問世并成功應用于乳腺癌的治療,相關的ToGA試驗證明曲妥珠單抗聯合化療藥物治療晚期胃癌取得了明顯的療效,死亡風險下降26%,中位生存期由11.1個月提高到13.8個月[20]。這一研究成為了晚期胃癌靶向治療的里程碑。曲妥珠單抗被應用于乳腺癌HER-2陽性患者的輔助治療后,被多項研究證實可以顯著提高乳腺癌手術患者的DFS與OS。未來,抗HER-2靶向治療在可手術胃癌患者輔助治療中的價值、在圍手術期化療中的價值、在進展期胃癌維持治療中的價值均有待進一步的研究。
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Association between HER-2 expression and the efficacy of postoperative adjuvant chemotherapy in gastric carcinoma
ZHOU Yi1LV Shi-jie2WANG Lan-jun3FAN Li-xin1#
1Department of Medical Oncology,the Third Hospital of Dalian,Dalian 116031,China
2Department of Obstetrics andGynecology,Dalian Maternity Hospital,Dalian 116033,China
3Department of Neurology,the Youyi Hospital of Dalian,Dalian 116100,China
objectiveTo analyze the patients with gastric carcinoma who received adjuvant chemotherapy after surgical resection,and to evaluate the correlation between the efficacy of adjuvant chemotherapy and HER-2 expression.Method185 cases of gastric cancer that were administered with postoperative adjuvant chemotherapy were analyzed retrospectively.The clinicopathological features,HER-2 expression,disease-free survival(DFS),overall survival(OS)were summarized,and the association between efficacy of adjuvant chemotherapy and HER-2 expression was investigated.ResultOf the 185 cases,141 were HER-2 negative(-),44 were HER-2 positive(+),with a positive rate of 24%.The HER-2 overexpression was closely related with tumor location,degree of differentiation and distant metastases,though no significant association with age,sex and TNM stage was observed.The DFS and median OS in the group of HER-2(+)were 9.1 months and 15.1 months,and were 15.2 months and 25.5 months in the group of HER-2(-)(P=0.046),respectively.Patients with HER-2(-)may benefit more from postoperative adjuvant chemotherapy compared with those with HER-2 (+),and the OS is comparatively longer(P=0.01).ConclusionPatients lacking HER-2 amplification may benefit from postoperative adjuvant chemotherapy with extended DFS and OS.
gastric carcinoma;adjuvant chemotherapy;HER-2;DFS
R735.2
A
10.11877/j.issn.1672-1535.2016.14.03.12
2015-11-02)
(corresponding author),郵箱:luckyflx@126.com