探讨局部晚期直肠癌术前新辅助放化疗疗效的预测因素，以指导直肠癌的个体化治疗。

回顾性分析南京医科大学第一附属医院2014年3月至2015年3月间收治的28例局部进展期直肠癌患者的临床病理资料，利用化学发光法检测新辅助放化疗前、后直肠癌患者血清癌胚抗原（carcino embryonie antigen，CEA）水平，以放化疗后肿瘤TNM分期降期与否和肿瘤消退程度（肿瘤长径）作为同步放化疗疗效的判断标准，分析CEA检测值的变化与直肠癌患者新辅助治疗疗效及预后等临床特征之间的关系。

病理完全缓解组(pathologic complete response，pCR)组与非pCR组患者，CEA的水平在新辅助治疗前后无统计学差异(p=0.069)，新辅助治疗后，CEA的下降程度在两组中未见差异（p=0.827）。经新辅助治疗后肿瘤长径退缩显著组，CEA下降程度也较显著，CEA下降≥50%组内，新辅助治疗后肿瘤长径退缩≥25%的患者占70.6%，CEA下降<50%组内，此部分患者仅占54.6%。

新辅助放化疗后CEA明显下降的患者其肿瘤退缩更显著，提示CEA可能作为一项直观的评估直肠癌新辅助放化疗的疗效指标。

To investigate the predictive factors of neo-adjuvant radio-chemotherapy for locally advanced rectal cancer, and to guide the treatment of rectal cancer.

Retrospective analysis of 28 locally advanced rectal cancer patients admitted in the First Affiliated Hospital of Nanjing Medical University from March 2014 to March 2015, with clinical and pathological data. The serum CEA level was detected by chemical luminescent assay, before and after neo-adjuvant therapy. The down-staging of tumor TNM stage and regression of tumor length were analyzed by postoperative pathology and MRI. The relationship between CEA levels and the effect of neo-adjuvant treatment were assessed.

There was no significance in the level of CEA difference between pCR group and non-pCR group before or after neo-adjuvant therapy (p=0.827). After neo-adjuvant therapy, more significant tumor regression (≥25%) was observed in patients that CEA decreased≥50%, amount for 70.6%, while the percentage was only accounted for 54.6% in patients that CEA decreased<50%.

CEA decreased significantly in patients with a greater degree of tumor regression after neo-adjuvant therapy, we can obtain more intuitive assessment of neo-adjuvant radio-chemotherapy efficacy in rectal cancer, especially in the tumor regression.