Since the mid-1980s, the U.S. Preventive Services Task Force has been responsible for making evidence-based recommendations about screenings and other preventive procedures that are designed to identify potential diseases. As colorectal cancer continues to be a major area of concern for many Americans, the recommendations for colorectal cancer screening tests have never been more relevant. Early detection of colorectal cancer remains the best chance of overcoming the disease, and that requires understanding the procedures and sequencing involved in the detection process.

Overview of Colorectal Cancer

Colorectal cancer is the umbrella term for cancer that starts in either the colon (colon cancer) or the rectum (rectal cancer). According to the American Cancer Society, colorectal cancer is the third most common cancer in the United States. In 2023 alone, for instance, there were over 150,000 new cases. Due to colon cancer screening initiatives and recent research about the various risk factors, the rate of new diagnoses has dropped slightly for older adults. At the same time, though, the rates have been increasing for people younger than 50.

In the vast majority of cases, colorectal cancer begins as a small growth along the lining of the large intestine called a polyp; most colon polyps start benign and remain benign, but around 5-10% become malignant and turn into a cancerous tumor. The timeline for a precancerous polyp to change into cancer is a slow process, however, and for most people it takes many years. For this reason, the symptoms also usually take years before they start manifesting; this is another reason why early detection is so important.

Risk Factors for Colorectal Cancer

In recent decades, researchers at the National Cancer Institute and other organizations have identified a number of risk factors that are believed to contribute to the development of colorectal cancer. While some of these risk factors are genetic or otherwise unchangeable, many are associated with lifestyle choices that can be addressed at any time:

  • Age: While rates have been increasing for younger people, it is still generally true that the risk of colorectal cancer increases as people age. Moreover, the majority of cases are diagnosed in individuals over the age of 50.
  • Medical history: Those who have a personal or family history of colorectal cancer or colon polyps are naturally at a higher risk, but there are several inherited genetic conditions that also increase the risk. Examples include Lynch syndrome and familial adenomatous polyposis (FAP), two conditions that are linked to specific genetic mutations that are known to lead to abnormal growths of cancer cells in the colon.
  • Chronic diseases: There are also some chronic gastrointestinal diseases that can increase the likelihood of cancer. The most common example is inflammatory bowel disease, a group of conditions in which inflammation can lead to abnormalities in the lining of the colon; the two principal types of this disease are Crohn’s disease and ulcerative colitis.
  • Diet: Consistent research has shown that a diet high in red meat (beef, pork, etc.) or processed meats (hot dogs and deli meats) can increase the risk of colorectal cancer. The risk is even more pronounced if the diet excludes healthy foods like fruits, vegetables, and whole grains.
  • Physical activity: Lack of exercise or other regular physical activity has also been associated with a higher risk of colorectal cancer.
  • Obesity: Being overweight or obese means a higher risk of a variety of medical conditions, including colorectal cancer. Improving one’s diet and exercising regularly, however, are both ways to find a healthy weight that avoids this type of risk.
  • Smoking and alcohol: As with being overweight, smoking and excessive alcohol consumption are associated with a variety of chronic diseases, but simply limiting or avoiding them can eliminate the factor altogether.

    Detection and Diagnosis of Colorectal Cancer

    Because colorectal cancer takes many years to develop and for symptoms to manifest, it’s highly likely that a patient will be unaware that the cancer is growing. This is why it’s so important to get cancer screenings at regular intervals at certain ages. The American Cancer Society now recommends that people at average risk get screened starting at age 45 (and earlier for people at higher risk), and there are several different diagnostic tests that can be used:

    • Colonoscopy: The longtime “gold standard” of colorectal cancer screening is a colonoscopy; while a patient is under sedation, a colonoscope is inserted through the rectum to directly visualize the entire colon. The gastroenterologist is on the lookout for polyps or other abnormalities that need further investigation. In some cases, a biopsy can be performed with tools mounted on the end of the colonoscope. A slight variation of this test is a flexible sigmoidoscopy, which is designed to examine only the last part of the colon.
    • Additional imaging tests: If a colonoscopy isn’t effective, a virtual colonoscopy (CT colonography) may be used instead; in this procedure, computed tomography (otherwise known as a CT scan) is used to produce images of the colon without actually inserting a device.
    • Stool tests: If prior test results do show abnormalities, a stool test may be the next step. In a fecal immunochemical test (FIT), for instance, a stool sample is tested for traces of non-visible blood that could indicate polyps or tumors in the colon. Another type, a fecal occult blood test (FOBT), also tests for trace amounts of blood;; the main difference between two is that FIT uses antibodies and FOBT uses a chemical called guaiac.

    In addition to determining whether or not cancer is present in the digestive tract, the different diagnostic tools are also the primary way a doctor determines the stage of cancer. Staging is a crucial step that typically involves assessing the size of the tumor, whether it has spread to nearby lymph nodes, and if it has metastasized to distant organs. Once the stage has been established, it is the main guide for further determining the treatment options.

    Colorectal Cancer Treatment Options

    As with other types of cancer, the treatment for colorectal cancer is dependent on a variety of factors, including the determination of the stage of cancer. Treatment options often involve a combination of approaches, and the specific plan is determined by a multidisciplinary team of healthcare providers. In general, though, there are three main categories of treatment:

    • Surgery: When the cancer is at an early stage, the first choice is usually surgery to remove the affected portions of the colon and rectum; this can include anything from removing individual polyps to resecting large portions of the colon. In later stages, it may also include removing nearby lymph nodes.
    • Chemotherapy: Chemotherapy is essentially the use of medication to kill or slow the growth of cancer cells. This approach can be used as the primary treatment, but it can also be used in combination with surgery either before or after the procedure.
    • Radiation therapy: Radiation therapy uses beams of high energy particles to target and destroy cancer cells. For some patients, radiation therapy is used alongside surgery and/or chemotherapy when other treatments aren’t effective.

      Schedule a Screening at Cary Gastro

      The possibility of developing colorectal cancer is a frightening thought for anyone, especially because of how long it takes to develop. At Cary Gastro, part of our dedication to providing excellent digestive healthcare is offering colorectal cancer screenings. This kind of preventive care is the simplest and easiest way to ensure that you don’t have cancer; but if you do end up developing it, it’s always better to catch it as early as possible. If you are 45 or older, or if you are at higher risk, contact us to request an appointment and be on your way to greater peace of mind.