What Is Bowel Cancer and How to Use a Home Test Kit for Bowel Cancer Screening?
Today, colorectal cancer is the third most common cancer and one of the major causes of malignancy in the world. Given that significant delays may occur between the development of the disease and the onset of symptoms, regular screening remains critical for the prevention of severe complications and death. Alongside various methods such as colonoscopy, the availability of fecal immunochemical tests (FIT) and guaiac-based fecal occult blood tests (gFOBT) as at-home detection kits have made screening for colorectal cancer easier than ever. Read along to learn more about colorectal cancer, its global incidence, symptoms, and screening via an at-home test kit.
What Is Bowel Cancer?
Colorectal or bowel cancer is a form of cancer that starts in the colon or rectum. The colon and rectum are parts of the large intestine in the gastrointestinal (GI) system. Although colorectal cancers may be referred to as colon and rectal cancers depending on the location of the initial cancerous growth. However, these conditions are often grouped together due to their shared attributes. The majority of colorectal cancers emerge as a growth on the inner lining of the colon or rectum, which are called polyps.
Colorectal polyps are categorized into three main groups based on their characteristics and cancer risk. The presence of adenomatous polyps, or adenomas, may indicate a pre-cancerous condition as they sometimes develop into cancer over time. Although they are more common and may require regular screening, hyperplastic polyps, and inflammatory polyps are typically not pre-cancerous. Similar to adenomas, sessile serrated polyps (SSP) and traditional serrated adenomas (TSA) are often associated with a higher risk of colorectal cancer.
If colorectal cancer develops in a polyp, it initially starts in the innermost layer of the colon and rectum wall. In time, it may proceed outwards into some or all layers of the wall and grow into different tissues, such as blood vessels or lymph vessels, which can travel to distant parts of the body. The stage of colorectal cancer depends on the depth of its growth into the wall and the state of its spread outside the colon or rectum.
How Common Is Bowel Cancer?
Although its incidence and mortality rates vary around the world, colorectal cancer is among the most common types of cancer and one of the major causes of cancer-linked deaths worldwide. According to GLOBOCAN 2020, colorectal cancer was estimated to account for around 10% of all new cases of cancer and 9.4% of all cancer-linked deaths. While the risks may vary from person to person, the overall lifetime risk of developing colorectal cancer is approximately 1 in 23 for men and 1 in 26 for women. Thanks to regular screening and the regulation of lifestyle-linked risk factors, the annual rate of colorectal cancers has been dropping since the 1980s. However, while incidence rates have continued to drop by around 1% in older adults, the rates have been observed to increase by about 1% to 2% among people younger than 50 throughout the last few decades.
What Are the Signs and Symptoms of Bowel Cancer?
Colorectal polyps or colorectal cancer may not always cause symptoms. In fact, there may be significant delays between the development of colorectal cancer and the onset of symptoms. However, in symptomatic cases, the condition may present with symptoms such as blood in or on the stool, changes in bowel habits, diarrhea, constipation, persistent abdominal pain or cramps, unexplained weight loss, narrow ribbon-like stools, and tenesmus, which is the feeling that the bowel does not empty all the way.
How to Use a Home Test Kit for Bowel Cancer Screening?
Various methods are available for screening colorectal polyps and colorectal cancers. The method to be used in a specific case may depend on the condition, medical history, family history, potential genetic syndromes, and preferences of the patient, alongside the availability of resources required for testing and follow-up. Flexible sigmoidoscopy is a procedure that involves the use of a long, thin, and flexible, lighted tube for the detection of polyps or cancer inside the lower third of a colon. Colonoscopy refers to a similar procedure that checks for polyps and cancer inside the rectum and the entire colon. During the colonoscopy, it is also possible to remove the majority of the polyps and some of the cancers.
Stool tests such as the guaiac-based fecal occult blood test (gFOBT), fecal immunochemical test (FIT), and the FIT-DNA test are currently the primary methods for screening for colorectal cancer. Colonoscopy is often preferred as a follow-up test if anything unusual is found during one or multiple of these tests. The guaiac-based fecal occult blood test (gFOBT) utilizes chemical guaiac to detect blood in the stool, whereas the fecal immunochemical test (FIT) uses antibodies for the same purpose. Both of these tests can be performed at home with a simple stool sample obtained with a stick or brush. Then, the test kit is returned to a doctor or a lab to check for the presence of blood in the collected samples.
On the other hand, the FIT-DNA test combines the fecal immunochemical test (FIT) with DNA detection and requires the collection of an entire bowel movement to be checked for altered DNA and blood in a lab. Finally, some rapid chromatographic immunoassays, such as our FOB Rapid Test Kit, allow for the qualitative detection of occult blood in stool in 15 to 20 minutes. These tests are suitable for point-of-care screening as they do not require the collected samples to be sent to a laboratory to process the samples or interpret the results.