People Are Getting Screened for Colon Cancer Without the Hassle. How?
Photo by Peter Schreiber Media
One of the most common ways to detect whether someone has an illness is by observing their symptoms, changes in the body that occur when a person has a disease or condition. For example, for the common cold, the symptoms include a runny or stuffy nose, sore throat, body aches, and much more. However, colon cancer, the third most common cancer in the world, accounting for approximately 10% of all cancer cases worldwide, in its early stages is often symptomless. Cancerous polyps and tumors can appear with barely any warning, with about 75% of colorectal cancers in adults under 50 diagnosed at an advanced stage. Nevertheless, with early screening, it is a preventable and treatable disease, and it is recommended to get a colonoscopy starting at the age of 45. Despite this, Colon cancer is becoming more prevalent even in younger adults under that age threshold. One of the reasons for this dramatic increase in the prevalence of colon cancer in the patient population is the lack of cancer screening. For patients, there is much discomfort and inconvenience in actually preparing the bowel for gastroenterologists to see potentially cancerous polyps in the colon.
Many adults do not want to have a colonoscopy done as the preparation traditionally includes being on a clear liquid diet the day before and then drinking 4 liters of a laxative to actually cleanse the colon. Nevertheless, there have also been developments for alternatives to this problem, including tablet-based colonoscopy prep and kits that require significantly less liquid for the person to actually drink to prepare for the colonoscopy. One of the more innovative tests to predict colon cancer is a blood-based test to detect tumor DNA in circulation, which is a much less invasive process to actually screen for the disease.
A study by researchers from the University of Maryland has extracted different types of data from 15 studies that used these DNA colon cancer tests across a wide range of patients. The main types of data that we are looking at from this are specificity and sensitivity data. Specificity data measures how accurate the test is in resulting in “true negatives,” meaning that the patient physically does not have the disease. Having a relatively high specificity rate (from 0% to 100%) indicates that the test rarely misdiagnoses healthy subjects. Sensitivity data practically does the opposite, measuring how accurate the test is in resulting in “true positives.” A relatively high sensitivity rate indicates that it is accurate in diagnosing subjects who actually have the disease.
The fifteen studies, overall involving 45,208 participants, were included in the analysis. The sensitivity rate was 82.7%, indicating strong performance in detecting patients who actually had the disease. The specificity rate was also high at 90.7%, demonstrating the accuracy of identifying patients without the disease. These blood-based DNA tests for colon cancer demonstrate high specificity and sensitivity, making them promising, accurate, scalable, and, most of all, patient-friendly screening tests. Their performance statistics also greatly exceed those of already established non-invasive screening tests. The forest plots below show each study’s specificity and sensitivity, and how close each is to the overall estimate. It also notes how many patients were included in each study. The size of the box and the length of the line for each study also emphasize the larger, more precise studies (larger boxes, shorter lines) in contrast to the smaller, broader, less precise studies (smaller boxes, longer lines).
Such non-invasive tests bridge the gap that prevents many adults from actually getting potentially life-saving screening for colon cancer. Combining the great performance of these tests with a more convenient screening process that can be used in the clinical setting not only improves fields where cancer screening has already been established, but also increases efficiency and changes the norms of how cancer screening operates today. With future research, these blood-based stool tests could completely transform cancer screening in general from a procedure that many avoid into non-invasive tests that are simple, widely accessible, and more effective for millions of people throughout the world.