175P - CEA clearance pattern is a strong predictor of pathologic complete response after neoadjuvant chemoradiation for rectal cancer: validation of FOWAR...

Date 17 December 2016
Event ESMO Asia 2016 Congress
Session Poster lunch
Topics Cytotoxic agents
Rectal Cancer
Surgical oncology
Presenter Huaabin Hu
Citation Annals of Oncology (2016) 27 (suppl_9): ix53-ix67. 10.1093/annonc/mdw581
Authors H. Hu1, J. Huang2, J. Zhang1, Y. Cai1, P. Lan3, J. Wang3, Y. Deng1
  • 1Department Of Medical Oncology, The Sixth Affiliated Hospital of Sun Yat-sen University, 510655 - Guangzhou/CN
  • 2Department Of Medical Oncology, Xiangya Hospital of Central South University, 410008 - Changsha/CN
  • 3Department Of Colorectal Surgery, The Sixth Affiliated Hospital of Sun Yat-sen University, 510655 - Guangzhou/CN

Abstract

Background

Approximately 10% to 30% locally advanced rectal cancer patients receiving neoadjuvant chemoradiation (CRT) will have a pathologic complete response (pCR). Predicting pCR can have a significant effect on patients in terms of helping confer prognosis, possibly enabling organ preservation, and potentially avoiding unnecessary surgery. The aim of this study was to investigate the predictive value of carcinoembryonic antigen (CEA) clearance pattern for the tumor response to neoadjuvant CRT in rectal cancer patients with elevated CEA levels (>5ng/ml).

Methods

Training set (TS) was based on a retrospective study of 75 rectal cancer patients undergoing neoadjuvant CRT and TME resection between 2012 and 2015. 71 of 495 patients with elevated CEA in FOWARC trial, who were randomly assigned to receive neoadjuvant CRT group were included in validation set (VS). Serum CEA were measured at four (TS) or six (VS) different time points, including base line, and the 2, 4, 6, 8 and 14 weeks during neoadjuvant CRT. An exponential trend line was drawn using the CEA values. Patients were categorized into two groups based on R2 values calculated through trend line, which indicates the correlation coefficient between exponential graph and measured CEA values: exponential decrease group (0.9

Results

CEA decrease with exponential pattern was a significant independent predictor for TRG (0-1) (TS: OR = 4.34, CI 1.40 - 13.48; VS: OR = 3.04, CI 1.10 - 8.43), good down-staging (ypTNM stage 0-I) (TS: OR = 4.70, CI 1.53 - 14.43; VS: OR = 7.26, CI 1.79 - 29.37) and pCR (TS: OR = 6.61, CI 1.01 - 40.54; VS: OR = 10.15, CI 1.50 - 68.62). The AUC (Area Under roc Curve) for pCR in TS and VS were 0.685 and 0.726, respectively, which was the strongest factor among clinicopathologic indexes.

Conclusions

The pattern of CEA clearance, a simple clinical parameter, normally available in everyday practice, was a independent predictor of pCR for rectal cancer patients. These results would be beneficial to guide individualized treatment strategies for this patients with elevated CEA levels, who were associated with poorer outcome.

Clinical trial indentification

NCT01211210

Legal entity responsible for the study

Huabin Hu

Funding

Guangzhou Science Funding

Disclosure

All authors have declared no conflicts of interest.