Noninvasive Test Detects Colorectal Cancer in Unscreened Patients

A noninvasive colorectal cancer-screening test detected the disease in patients who had previously avoided more invasive screening measures. Colorectal cancer is the second deadliest form of cancer in the USA and this year, nearly 135,000 Americans will be diagnosed with the disease and 50,000 Americans will die of it.

The US Food and Drug Administration (Silver Springs, MD, USA) approved a multi-target stool DNA test (mt-sDNA) that detects the presence of red blood cells and DNA mutations that can be associated with colon cancer. In 10,000-patient, prospectively conducted clinical trial the test showed 92% sensitive for detecting colorectal cancer and 42% sensitive for precancer, with a specificity of 87%.


Physicians at the USMD Physician Services (Dallas, TX, USA) performed a retrospective medical records review of eligible patients and focused on patients at average risk for colorectal cancer, those without symptoms, a personal or family history of colorectal cancer, or polyps, which were not previously compliant with recommended guidelines for screening. During the 12-month study period, from October 2014 to September 2015, USMD providers ordered 393 mt-sDNA studies, and 347 patients completed the test, achieving 88.3% compliance.

Fifty-one patients, representing 14.7% of the total, tested positive by the Cologuard mt-sDNA test (Exact Sciences Corporation; Madison, WI, USA) and were referred for diagnostic colonoscopies. There were 46 patients, or 90.2% of those referred, received the follow-up colonoscopies. Three patients refused the procedure and two patients did not respond to physicians' attempts to follow up. Among the 46 patients who had follow-up colonoscopies, four were diagnosed with colon cancer. Twenty-one were diagnosed with advanced adenoma, or polyps; nine had non-advanced adenoma; and 12 tested negative.

Mark Prince, MD, MBA, a director of gastroenterology with USMD Physician Services, said, “Despite the availability of various colon cancer screening options, more than 40% of Americans are not getting screened. This study highlights the opportunity to expand the screening population by offering new, patient-friendly methods. We were interested to see whether the 'real-life' experience with Cologuard in clinical practice would be similar to the results seen in the clinical trial. Colon cancer screening saves lives. Colonoscopy is the best form of colon cancer screening, but for patients who will not have a colonoscopy, a noninvasive screening test like Cologuard is needed.” The study was presented at the American Association for Cancer Research (AACR) Annual Meeting, held April 16–20, 2016, in New Orleans (LA, USA).

Related Links:
US Food and Drug Administration
USMD Physician Services
Exact Sciences