P-295 - CA 11-19: A Tumor Marker to Detect Colorectal Cancer

Date 04 July 2015
Event WorldGI 2015
Session Posters
Topics Biomarkers
Cancer Aetiology, Epidemiology, Prevention
Colon Cancer
Rectal Cancer
Presenter B. Overholt
Citation Annals of Oncology (2015) 26 (suppl_4): 1-100. 10.1093/annonc/mdv233
Authors B. Overholt1, D. Wheeler1, T. Jordon1, H. Fritsche2
  • 1Knoxville/US
  • 2Houston/US

Abstract

Introduction

Colorectal cancer remains the third most frequent cause of cancer deaths globally. Both fecal DNA/hemoglobin and blood tests using tumor related antigens are increasingly being used to monitor treatments and in some cases aid in diagnosing colorectal cancers. However, higher sensitivity and specificity are needed before an acceptable tumor antigen blood test for colon cancer is clinically useful.

Methods

Using a monoclonal ELISA assay, a new colon cancer antigen, CA 11-19TM, (100 kDa glycoprotein) was measured in 522 colonoscopy confirmed patients including normal, benign GI diseases, polyps and colon cancer in a blinded IRB approved study.

Results

Using a cutoff of < 6.5 units/ml as normal, CA 11-19 was positive (>6.5) in 132 of 139 of colorectal cancer cases. 100% of 63 cases of Stage I and II were positive. Sensitivity of CA 11-19TM for diagnosis of overall colorectal cancer was 97.7%. Negative results were found in 86.1% of normals (124/144) and 83% of benign GI diseases (151/182). The specificity for the assay was 83.4% for all benign groups combined (275/326).

Conclusion

CA 11-19TM is a serologic tumor marker for colorectal cancer with a demonstrated sensitivity of 97.7% and a specificity of 84.4%. Diagnostically, a positive assay result increases the odds of finding colorectal cancer by a factor of five. The test appears to be highly sensitive for detection of early stage colorectal cancer. Additional prospective studies are needed to validate the use of CA 11-19TM as an aid in the diagnosis of colorectal cancer.