目的： 研究左半结肠癌和直肠癌患者的临床病理特征及生存期之间的差异。 方法： 选取2011年1月至2012年1月在 第二军医大学长海医院行手术切除的323例原发性结直肠癌患者为研究对象，收集患者临床特征资料，以手术日期或病理确诊日 期为随访起点对患者或家属进行随访，以死亡为终点事件，随访时间截至2017年8月1日。 结果： 左半结肠癌和直肠癌患者在首 发症状、组织学类型、肿瘤分期、术前是否贫血、p53阳性率及 BRAF 基因突变状态之间差异有统计学意义（ χ 2 =59.088，4.188， 24.305，11.956，4.221，4.001；均 P <0.05）。左半结肠癌和直肠癌中位生存时间均未观察到。左半结肠癌、直肠癌的5年生存率分别 为79.2%、74.3%。Ⅰ期、Ⅱ期左半结肠癌和直肠癌患者生存曲线差异无统计学意义（ P> 0.05），Ⅲ期左半结肠癌和直肠癌患者生存曲 线差异无统计学意义（ P >0.05）。Cox比例风险分析结果显示，病理类型( HR =1.759， P <0.05)和肿瘤分期( HR =2.104， P <0.01)是影响 结直肠癌患者OS的独立危险因素。 结论 ：左半结肠癌和直肠癌生存时间未见不同，病理类型及肿瘤分期可能为结直肠癌患者 OS的影响因素。

Objective: To compare the differences in clinical and pathological features and survival time between patients with left -sided colon cancer and rectal cancer. Methods: A total of 323 patients with colorectal cancer (CRC) underwent surgical resection at Changhai Hospital of the Second Military Medical University between January 2011 and January 2012 were enrolled in this study. The clinical data of patients were collected and the follow-up was started from the day of surgery or pathological confirmation with the death of patients as endpoints. The follow-up lasted untilAugust 1,2017. Results: There were significant differences in initial symptoms, pathologic type, tumor stage, anemia before surgery, p53 positive rate, and BRAF mutation (χ 2= 59.088，4.188，24.305，11.956，4.221，4.001，all P<0.05) between patients with left-sided colon cancer and rectal cancer. For all the patients, the median survival time was not observed. The five-year survival rates of patients with left-sided colon cancer and rectal cancer were 79.2% and 74.3%, respectively. The Kaplan-Meier survival curves of patients at StageⅠ-Ⅱshowed that there was no statistical difference between patients with left-sided colon cancer and rectal cancer （P=0.840） and the survival of Stage Ⅲ patients between the two groups also showed no statistical difference (P=0.106). Cox regression analysis showed that both the pathologic types [HR=1.759, P=0.047] and tumor stage [HR=2.104, P<0.001] were independent predictive factors for OS of CRC patients. Conclusion: There were no differences in survival time between patients with left-sided colon cancer and rectal cancer. The pathologic types and tumor stage were factors influencing the OS of CRC patients.