A blood-based screening method may pave the way for colon cancer to have more efficient diagnostic standards. In a new study from the University of Wisconsin-Madison, researchers discover four blood-based markers that are linked to pre-cancerous states of colon cancer, which may eventually lead to the disease.
Current colon cancer screening practices usually yield low compliance rates and overdiagnosis. The disease is highly curable if detected early. With this, people may think screening should be pretty straightforward, but that is not the case.
The ultimate goal of the study is to develop a blood test that can detect colon cancer.
"This study is the first peek at the possibility that there will be blood markers for a minimally-invasive procedure that can reduce over-diagnosis," says Bill Dove, study senior author and professor of oncology and genetics with the McArdle Laboratory for Research and Carbone Cancer Center at UW-Madison. "They do exist."
Colon Cancer Screening At Present
The best practice for colon cancer diagnosis is to perform optical colonoscopy. The procedure requires patients to empty their bowel before undergoing the invasive diagnostic test. The complexity this entails also contribute to low-compliance rates. During the procedure, the doctor looks out for polyps, which will in turn be handed to the laboratory for testing.
Another option for colon cancer screening at present is computed tomography. This requires the same bowel preparation, but the procedure itself is not invasive. Doctors may order colonoscopy and polyp removal after CT scan if necessary.
For the new study, the research team discovered that most of the small polyps detected during testing will never turn cancerous thus, treating them is unnecessary.
The authors looked for proteins that are elevated in the blood of patients with cancerous disease, but not elevated in patients whose polyps are not growing, or those who do not have polyps at all.
The researchers investigated blood samples from 90 optical colonoscopy patients. They divided it into groups of no, low-risk or high-risks pre-cancerous polyps, and 31 CT scans of patients who were studied but did not have polyp removal.
The next step was to choose 19 proteins that were previously known to be high in rodent samples. They then performed mass spectrometry, which calculates protein concentration in blood.
Lastly, the researchers correlated the blood markers with the colonoscopy outcomes. In this way, they were able to identify which markers are particularly linked with cancerous polyps.
Lead author Melanie Ivancic said the study findings revealed four elevated proteins that are related with early colon cancer.
Dove said he sees a possible blood-based test to complement other techniques for colon cancer screening.
The study was published on April 8 in the Proceedings of the National Academy of Sciences.