ASCO, the American Society of Clinical Oncology, released the results of a “large, multinational prospective screening study of nearly 8,000 individuals called PRESEPT”. Pre-SEPT because the study explored a DNA biomarker for colorectal cancer known as Septin 9. The test is both sensitive, 90%, meaning it picks up almost all cases, and specific, 89%, meaning it weeds out false positives. For more on sensitivity and specificity, which are very important for determining whether a test should be considered a valid way to check for disease, read more here.
Importantly, the majority of the patients used in the study were of early stage; 87% of stage I and II specimens demonstrated methylated SEPT9. SEPT9 methylated DNA was detected in blood specimens taken from individuals with tumors arising in all locations of the colon and rectum, including right-sided tumors which have proven difficult to detect by endoscopic methods. SEPT9 methylation was analyzed using adenoma and polyp tissue specimens; methylation was shown to occur early in the progression of CRC and could be a useful tool for evaluating biopsies.
This is very important news for over 40 million Americans who do not comply with colonoscopy recommendations. The outcome of detecting early stage tumors is excellent! My research indicates that one very commonly used lab carries this test, Quest Diagnostics, here is the link: ColoVantage. It seems that Quest charges $355, but I found a lab called eStatLab that charges $260 for the same test.
All of the different components of a colonoscopy typically total about $1,400, so this could be a significant help for people who have no insurance. When combined with other tests, such as the fecal occult blood test and the CEA, carcinoembryonic antigen, the results can paint a very good picture of the potential for colorectal cancer.