A liquid biopsy can detect colorectal cancer at an early stage and with accuracy near 90%, according to research scheduled to be presented at the 2018 Gastrointestinal Cancers Symposium (January 18-20, 2018; San Francisco, CA).
"Our study is important because there is still some reticence among patients to use stool-based tests or have an invasive exam like colonoscopy to detect colorectal cancer," said Wen-Sy Tsai, MD, PhD, assistant professor, Linkou Chang Gung Memorial Hospital (Taipei, Taiwan), in a statement (January 16, 2018). "Our results may point to a solution for people who are reluctant to get an initial screening colonoscopy or are not compliant in returning stool-based test kits that they get from their doctors."
Dr Tsai and colleagues conducted a study enrolling 620 patients over 20 years of age who were frequent hospital visitors for routine colonoscopies or a confirmed colorectal cancer diagnosis. Prior colonoscopy or biopsy results showed 438 of the patients had either adenomatous polyps or early to late-stage colorectal cancers. Remaining participants—designated as the control group—showed no signs of a pre-cancerous growth or colorectal cancer.
All of the patients had their blood tested for circulating tumor cell analysis through a routine blood draw. The resulting samples were processed using CMx, an assay that captures rare circulating tumor cells on a liquid-coated chip that mimics human tissue. Results of these assays were further compared in a blinded analysis with the colonoscopy results.
Results of the study showed that sensitivity ranged from 77% for detection of circulating tumor cells in polyps to 87% for stage I-IV cancers. After calculating the accuracy of the results by taking into account sensitivity and specificity, researchers found the accuracy of the test ranged from 84% to 88% between polyps and cancerous samples.
Additionally, they noted that the accuracy of this test was superior to that of fecal occult blood testing (FOBT).
"Recent surveys have found that over 80% of patients who are reluctant to undergo colonoscopy screening would be receptive to a blood test over stool-based tests," said co- Ashish Nimgaonkar, MD, gastroenterologist and Medical Director, Center for Bioengineering Innovation and Design, Johns Hopkins University, in a statement (January 16, 2018). "A number of studies have found that affordability was the number one reason for not being screened; however, this test is highly affordable and can potentially cost less than $100."
Their test, researchers added, could be used with other solid tumors, such as breast, lung, and prostate cancer.—Zachary Bessette