Not very long ago we brought you the news that a new blood test had been developed to test for colorectal (CRC) cancer. This past week, the FDA approved the test, called Shield, produced by the drug manufacturer Guardant. Endorsed by both the American Cancer Society and the US Preventive Services Task Force, this new blood test should be commercially available with a prescription in the coming weeks and should be covered by both Medicare and private commercial insurance. As we have previously noted, a significant portion of the adult population has not been screened for colon cancer with either a colonoscopy or fecal test, so the hope is that this new blood test will encourage those holdouts to use this new, simple option as a way to get screened. While this blood test will not give you the accuracy achieved through a colonoscopy (and it barely picks up the presence of precancerous polyps), it does detect Stage I CRC 65% of the time and is much more sensitive for picking up stage II and stage III (100% of the time). This level of sensitivity is similar to that achieved through stool sample tests.  Just as with a stool test, a positive blood test would then need to be followed up with a colonoscopy for a more definitive diagnostic assessment.

While a colonoscopy remains the “gold standard” it’s clear that for many reasons, including cost, invasiveness, preparation, and time, many adults never quite make it to a colonoscopy center, and therefore lose out on the opportunity to diagnose, treat or even prevent the occurrence of CRC. While a blood test or stool sample may not be as valuable for preventing the occurrence of CRC in the first place, if these tests are acceptable and accessible, and therefore used by people who would otherwise avoid a colonoscopy, they may save thousands of people who might otherwise die from colorectal cancer. One interesting thing to note about the colonoscopy: A recent study published in JAMA Oncology reported that for people with average risk of CRC (no family history or other risk factors), it may be fine to screen with a colonoscopy every 15 years, rather than the current recommended period of every 10 years. GIven the challenge to many of accessing a colonoscopy, and the inadequate number of doctors available to perform the test, for those with average risk and no previous positive colonoscopy test, waiting an additional 5 years for a follow-up does not appear to increase your risk of being diagnosed with CRC or dying as a result of the disease. For more on this study, pull out your date planner and click here.

The at-home stool test for CRC remains a very viable option for those who don’t want to go through a colonoscopy but also may not want, or cannot access, the new blood test. In fact, according to a recent study published in JAMA Network Open, this simple at-home test can reduce your risk of dying from CRC by 33%. For people with average risk, it’s been suggested that this kind of test is as good as a colonoscopy every 10 years, assuming you take the fecal test annually. Of course, similar to the blood test, an abnormal fecal test would need to be followed up by a colonoscopy. Currently, there are 3 types of at-home fecal tests available for use. One uses chemicals to look for blood in the stool, one utilizes antibodies to look for blood in the stool and the third (Cologuard) identifies DNA from cancer cells in the stool and has an antibody component to look for blood. The third test (which only needs to be taken every 3 years) is thought to be the most accurate (even better than the blood test) and the other 2 tests should be done every year. For some tips on how to successfully undertake an at-home fecal test, grab some toilet paper and look here.

Even though colon cancer diagnoses are said to be on the decline for those over 65 (and increasing for those under 45), those who are 76 and older are at the greatest risk for developing CRC. And while screening is not recommended for those over 85, for those ages 76-85, the decision as to whether to screen and test should be a personalized one, depending on the specific circumstances of the patient. As with all tests, the question is whether the benefits of the test outweigh the risks. And if worrisome symptoms arise (including blood in your stool, abdominal pain, unexplained weight loss, or a change in bowel habits), you and your doctor may determine that such a test is called for. Perhaps better safe than sorry. For one individual’s story of putting off a test as he believed himself too healthy for such a disease (and therefore missed an early diagnosis), take a look here.