Bevacizumab and Combination Chemotherapy in Treating Patients With Previously Untreated Metastatic Colorectal Cancer That Cannot Be Removed By Surgery

RATIONALE: Monoclonal antibodies, such as bevacizumab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Drugs used in chemotherapy work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving bevacizumab together with combination chemotherapy may kill more tumor cells.
PURPOSE: This phase III trial is studying how well giving induction therapy with bevacizumab together with combination chemotherapy with or without capecitabine followed by bevacizumab maintenance therapy in treating patients with metastatic colorectal cancer that cannot be removed by surgery.

原理：贝伐珠单抗（bevacizumab）等单克隆抗体可通过多种不同途径阻断肿瘤生长。部分单克隆抗体可抑制肿瘤细胞的增殖与扩散能力；另有部分可靶向识别肿瘤细胞，协助杀伤肿瘤细胞，或携带抗肿瘤物质抵达肿瘤部位。化疗药物可通过多种机制抑制肿瘤细胞增殖，既可直接杀伤肿瘤细胞，也可阻止其分裂增殖。将贝伐珠单抗与联合化疗方案联合应用，或可杀伤更多肿瘤细胞。
试验目的：本项III期临床试验旨在评估针对不可手术切除的转移性结直肠癌患者，采用贝伐珠单抗联合含或不含卡培他滨（capecitabine）的联合化疗方案开展诱导治疗，后续予以贝伐珠单抗维持治疗的临床疗效。