大腸直腸癌病人根除性切除手術後預後因子與轉移性大腸直腸癌病人預測因子研究

The study for prognostic factors of patients with radical resection of colorectal cancer and predictive factors of patients with metastatic colorectal cancer

蔡祥麟(Hsiang-Lin Tsai)

指導教授 ： 王照元

高雄醫學大學/醫學院/醫學研究所博士班/博士(2016年)

摘要

大腸直腸癌是全世界最常見的惡性腫瘤之一，近年來在亞洲國家它的發生率及死亡率在過去這幾十年來都呈現有顯著的增加。在臺灣，大腸直腸癌除了是發生率第一位的惡性腫瘤外，同時也是男、女性中因癌症相關死亡的第三位；依行政院衛生福利部國民健康署的最新資料顯示，過去十年來台灣大腸直腸癌的年發生率已達43.5%，每年的新個案超過15,000人；每年更有超過5,000人是因為大腸直腸癌而死亡。
雖然，手術切除對大腸直腸癌的局部病灶的控制有很高的效益；但是接受根除性手術的病人中會有25 ~ 40%發生復發的現象。大腸直腸癌的復發是具有時間限制性的現象，復發的病人中有40 ~ 50%出現在最初手術後的一年內(早期復發)；而90%的復發則出現在手術後的四年內。有文獻指出由初次治療開始到復發的時間是與病人的存活率有強烈的相關，特別是那些術後一年內復發的病人(早期復發的病人)更明顯。很不幸地，目前還沒有一個理想的生物標誌或是指標因子可以在病人術後監測期間用來預測這個疾病的早期復發。然而，一個簡單且可靠用來偵測術後早期復發的生物標誌將可以幫助醫師在病人的治療上更早期規劃一個更有效的治療計畫。
最近許多研究文獻顯示，分子標誌的結合在於預測病人的臨床結果的能力上跟病理性的分期或是臨床上的分期是更佳的。甚至有文獻建議針對個別大腸直腸癌病人的分子特徵去做瞭解是可以來釐清腫瘤特徵，因此而能找出高危險性復發的病人；甚至可以調整對於癌症治療的觀念。本研究論文的目地就是在於尋找出接受根除性手術的大腸直腸癌病人術後早期復發相關的臨床病理因子及生物標誌。
吾人的研究論文內容主要分為下列四個部分。第一部分:闡述目前臺灣大腸直腸癌的現況及研究大腸直腸癌術後早期復發的背景跟動機。第二部分:藉由GeXP來分析比較大腸直腸癌腫瘤組織與正常組織中候選基因表現量的差異，再由候選基因中挑選最佳的基因來進行術後早期復發的研究，並探討這些與術後早期復發高度相關的基因對於接受根除性手術病人的臨床重要性。在此部分的研究顯示血管內皮生長因子(VEGF)與術後的早期復發有高度相關，當血管內皮生長因子(VEGF)蛋白質過度表現時會造成病人術後的早期復發(P = 0.023)及較差的無病存活率(P < 0.001)與總體生存率(P = 0.002)。此外，還有一些臨床病理因子諸如血管侵犯(P = 0.048)；周邊神經侵犯(P = 0.042)及術後不正常的腫瘤胚胎抗原值(P = 0.004)都跟術後的早期復發相關。第三部分: 嘗試分析治療中(peritherapeutic)血管內皮生長因子生長因子表現量的下降可以做為接受轉移性大腸直腸癌病人以FOLFIRI加Bevacizumab做為第一線治療之反應的預測因子。第四部分:藉由微小核醣核酸矩陣找出與接受根除性手術的大腸直腸癌病人術後早期復發相關的微小核醣核酸；並進一步探討這些與早期復發高度相關的微小核醣核酸對於病人臨床結果的影響及意義。在此部分研究，吾人選擇微小核醣核酸-148a (miRNA-148a; miR-148a)做為研究標的，結果顯示組織中或是血清中微小核醣核酸-148a(miRNA-148a; miR-148a)表現量下降會造成病人術後的早期復發。進一步的細胞實驗顯示微小核醣核酸-148a會抑制腫瘤細胞的增殖(P = 0.0002)，移動(P = 0.0001)及使細胞周期停止在G2期(P = 0.008)。動物實驗則顯示微小核醣核酸-148a (miRNA-148a; miR-148a)會抑制腫瘤細胞的體積(P = 0.0354)。而高表現的微小核醣核酸-148a也會有較佳的無病存活率(P = 0.0006)與總體生存率(P = 0.0156)。最後，吾人希望進一步找出微小核醣核酸-148a (miRNA-148a; miR-148a)與血管內皮生長因子(VEGF)間的關聯性，以釐清分子機制期待能找出抑制病人術後的早期復發的完整的作用機制與未來發展治療策略參考。
本論文的研究目的是期望能提供一個省時、正確、高效能的癌症早期診斷技術，後續有可能有效地在臨床診斷與治療策略的運用、改進根除性手術預測早期復發的精確性甚至於儘早積極的介入治療，以增加病人的存活率。

關鍵字

大腸直腸癌 ； 根除性手術 ； 術後早期復發

並列摘要

Colorectal cancer (CRC) is one of the most common cancers in Asian countries, and its incidence and mortality have increased significantly during the past several decades. In Taiwan, CRC is also the third major cause of cancer-related death. The annual incidence of colorectal cancer has increased up to 43.5% in the past 10 years, with >15,000 new cases of colon cancer and >5,000 cancer-related death from colon cancer each year; among these patients.
Although surgical resection can be highly effective for localized disease, 25 ~ 40% of patients develop recurrence after curative surgery. The recurrence of CRC is, for the most part, a time-limited phenomenon; 40 ~ 50% of recurrences become apparent within the first year after the initial surgical resection (postoperatively early relapsed) and 90% appear within the first 4 years. It has been shown that the time from the initial treatment to recurrence is related strongly to survival, and this is especially with regard to patients who experience recurrence within 1 year of their surgical resection (early relapse). Unfortunately, no ideal biomarker or indicator is available to predict early relapse of this disease during patient monitoring. A simple and reliable biomarker for the detection of postoperative early relapse is needed. Using biomarker is able to assist physicians in planning more efficient therapies at an earlier stage of a patient’s treatment.
Recently, many studies have revealed that a combination of molecular markers may be equivalent to pathological or clinical staging in predicting clinical outcomes. Moreover, it has been suggested that understanding molecular features that determine the behavior of individual CRC may be a fundamental step in identifying high-risk patients, thus allowing for the modulation of cancer treatment options. The purpose of this study is to investigate the potential clinicopathologic factors and molecular biomarkers for the prediction of early relapse of CRC patients with curative resection.
In this study, I divided my study into four parts to complete my researches. In the first part, I clarified that the status and importance of CRC in Taiwan. I also demonstrated that the background and motivation of my study for the early relapse in CRC patients with curative resection. In the second part, I analyzed the difference of candidate genes between the tumor tissues and the normal tissues by GeXP analyses first and then I chose the best candidated genes to confirm the correlation between genes and early relapse. Furthermore, I investigated the importance of the highly-related candidate genes in clinical outcomes of CRC patients with curative resection. Herein, I found the vascular endothelial growth factor (VEGF) to be highly related with early relapse (P = 0.023). It demonstrated that the overexpression of VEGF protein resulted in poorer disease-free survival rates (P < 0.001) and poorer overall survival rates (P = 0.002). Moreover, there were some clinicopathologic factors which were highly related with early relapse, for example, vascular invasion (P = 0.048); perineural invasion (P = 0.042) and high postoperative carcinoembryonic antigen (CEA) level (P = 0.004). In the third part, I tried to analyse the role of peritherapeutic decreased vascular endothelial growth factor (VEGF) in metastatic colorectal cancer (mCRC) patients with FOLFIRI plus Bevacizumab as first-line treatment. We demonstrated that decreased peritherapeutic tissue VEGF IHC scoring could predict better responses and better progression-free survival rates (P = 0.033). In the fourth part, I used the microRNA (miRNA) arrays to compare the miRNA profiles in CRC tissue samples of early- and nonearly-relapse patients. I identified a promising candidate, miRNA-148a, to validate and illustrate the role in CRC recurrence via in vitro and in vivo. In vitro, it revealed that miRNA-148a could inhibit the proliferation (P = 0.0002), migration (P = 0.0001) of the tumor cells and arrest at G2 phase (P = 0.008). In vivo, it demonstrated that miRNA-148a could inhibit tumor growth volume (P = 0.0354). It also showed that high expression of miRNA-148a had better disease-free survival rates (P = 0.0006) and overall survival rates (P = 0.0156). Finally, I would like to find out the correlation of miRNA-148a and VEGF to complete the mechanism and further develop a therapeutic strategy.
After accomplishment of this study, an innovated biomarker would be established, and subsequently the efficiency of clinical implication and accuracy of predicting early relapse after radical resection may be improved, and the intensive treatment might be initiated. We anticipate these results may afford a time-saving, effective, high-throughput and innoviated colorectal diagnostic technique and treatment strategy.

並列關鍵字

colorectal cancer ； radical resection ； postoperative early relapse

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