A noninvasive colorectal cancer screening test detected the disease in patients who previously avoided other screening measures, according to a recent study.1 The study of nearly 400 patients revealed four patients with cancers and 21 with advanced adenoma, or polyps.
A clinical trial for Cologuard by Exact Sciences, Madison, Wis, previously demonstrated that the test is 92% sensitive for detecting colorectal cancer and 42% sensitive for precancer, with a specificity of 87%.
“Despite the availability of various colon cancer screening options, more than 40% of Americans are not getting screened,” says Mark Prince, MD, MBA, a director of gastroenterology with USMD Physician Services, Dallas. “This study highlights the opportunity to expand the screening population by offering new, patient-friendly methods.”
In the recent study, Prince and colleagues performed a retrospective medical records review of Medicare-eligible patients treated by physicians of USMD Physician Services. The study focused on patients at average risk for colorectal cancer—those without symptoms, a personal or family history of colorectal cancer, or polyps— who were not previously compliant with recommended guidelines for screening.
“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,” says Prince.
Clinicians offered Cologuard screening to patients who had not undergone colonoscopy screening in 10 or more years, or a fecal occult blood test in a year or more. During the 12-month study period, from October 2014 to September 2015, USMD providers ordered 393 multitarget stool DNA (mt-sDNA) studies, and 347 patients completed the test, achieving 88.3% compliance. Among the study participants, 51 patients, representing 14.7% of the total, tested positive by Cologuard and were referred for diagnostic colonoscopies.
Among the 46 patients who underwent follow-up colonoscopies, four were diagnosed with colon cancer; 21 were diagnosed with advanced adenoma, or polyps; nine had nonadvanced adenoma; and 12 tested negative.
Prince says the discovery of four cases of colon cancer and numerous polyps, which have the potential to develop into cancer, supported the findings of the earlier clinical trial. None of the patients had reported any symptoms, and all had previously refused colonoscopies.
“Colon cancer screening saves lives,” Prince says. “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.”
Colorectal cancer is the second deadliest form of cancer in the United States. This year, nearly 135,000 Americans will be diagnosed with the disease, and 50,000 Americans will die of it.
Prince says a limitation of the study is that it involved only patients who were eligible for Medicare. “It will be interesting to analyze the use in commercially insured patients when insurance coverage becomes more widespread,” he says, adding that any positive results from noninvasive screening tests should be followed up by a colonoscopy.
In August 2014, FDA approved Cologuard, a multitarget stool DNA test (mt-sDNA) that detects the presence of red blood cells and DNA mutations that can be associated with colon cancer. In October 2014, Cologuard was approved for Medicare coverage.
- Prince M, Lester L, Chinawala R, et al. Multitarget sDNA increases colorectal cancer screening among previously noncompliant patients: the USMD physician services experience [abstract]. Presented at the American Association for Cancer Research annual meeting (New Orleans: April 16–20, 2016).