MESH: A Non-Randomised Phase II Trial of Methotrexate in Metastatic Colorectal Cancer with MSH2 Deficiency

Primary objectives: To determine the efficacy (by response rate using RECIST criteria) of methotrexate in patients with metastatic colorectal cancer and evidence of MSH2 deficiency previously treated with standard chemotherapy.
Primary endpoints: The primary endpoint will be the objective response rate to treatment (ORR) (to include radiological evidence of confirmed complete response and partial response), as defined by RECIST criteria on CT scans.

主要研究目标：针对既往接受过标准化疗的伴MSH2缺陷的转移性结直肠癌患者，评估甲氨蝶呤的疗效，疗效以基于实体瘤疗效评价标准（Response Evaluation Criteria in Solid Tumors，RECIST）的应答率为评价指标。
主要研究终点：治疗的客观缓解率（Objective Response Rate，ORR），即依据实体瘤疗效评价标准（RECIST），通过计算机断层扫描（Computed Tomography，CT）评估的、涵盖经影像学证实的完全缓解与部分缓解的病例占比。