To Explore The Potential Correlation Between Carcinoembryonic Antigen(CEA) Level And The Tumor Response Of Rectal Cancer

PurposeWe aim to explore the carcinoembryonic antigen(CEA)level befor preoperative chemoradiotherapy(CRT)predicting pathologic complete response(pCR)in locally advanced rectal cancer undergoing CRT.Furthermore,we evaluate whether the change of before and after preoperative chemoradiotherapy(CRT)in rectal cancer affects tumor response.MethodsWe retrospectively analyzed 187 rectal cancer patients who underwent preoperative CRT followed by curative surgery,and all of witch were treated in Tumor Hospital of Liao Ning Province during 2012 to 2017.All patients received preoperative radiotherapy of 45-50.4 Gy in 25-28 fractions with 5-fluorouracil,capecitabine or F.FOX/X.LOX Total mesorectal excision was performed 4 to 8 weeks after preoperative CRT.CEA levels were checked before and after CRT.Clinical and pathologic factors were analyzed for tumor response.ResultsPre-CRT CEA level(cutoff value,5 ng/mL)was not a significant factor for tumor response on the multivariate analysis(p= 0.971).Patients were categorized according to the pre-and post-CRT CEA level(group CEA H-N:pre-CRT CEA<5 ng/mL;group CEA H-N:pre-CRT CEA>5 ng/mL and post-CRT CEA<5 ng/mL;group CEA H-H:pre-CRT CEA>5 ng/mL and post-CRT CEA>5 ng/mL).Both the tumor regression and tunmr downstage were significantly higher in group CEA H-N than in groups CEA N-N and CEA H-H[73.5%(36/49)、57.1%(68/119)and 36.8%(7/19)(p=0.016)];[61.2%(30/49)、46.2%(55/119)and26.3%(5/19)(p=0.028)].However,there is no significant difference for pCR groups CEA N-N、CEA H-N and CEA H-H(all,p =0.254).ConclusionsDecline of elevated CEA level(>5 ng/mL)during preoperative chemoradiotherapy has significant effect on tumor response in rectal cancer.Pre-CRT CEA level was not a significant factor fo predicting pCR on the multivariate analysis).