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.