Understanding colorectal (colon) cancer
Our gut has been getting a lot of attention in recent years. It’s a powerful, complicated system that can easily get out of whack. Nutrition, stress and lifestyle habits all help play an important role in our gut health. Speaking of important roles, our colon (large intestine) is a part of the digestive system that helps absorb water and minerals and eliminate waste. The colon is an essential part of our system. But, if cells grow abnormally in the colon or rectum, colon polyps may form. And, depending on the type of polyp, it might turn into colorectal cancer (colon cancer) over time (usually many years).1, 2
What are the types of colon cancer?
Most colon cancers are called adenocarcinomas. These tumors start in the cells that make mucus to lubricate the inside of the colon and rectum. Other types of colon cancers exist but are rare. They include:3
- Carcinoid tumors
- Gastrointestinal stromal tumors
Did you know a polyp may take up to 15 years before it turns into cancer? That’s a long time. Regular screenings may help spot polyps early and could even help prevent them from turning into cancer. So, even if you don’t have symptoms, you may want to consider getting regular colon cancer screenings once you turn 50. (Some experts say 45.) If you have any risk factors (read on to learn about these), talk to your doctor about getting screened before you hit the big 5-0.4, 5
Here’s a little bit about each type of colon cancer screening. Be sure to chat with your doctor about which one may be right for you.6
- Stool test: There are three types of stool tests. The guaiac-based fecal occult blood test and fecal immunochemical test both check for blood in your stool (blood could be an indicator that there’s a polyp or cancer). Both kinds of tests are done once a year. The stool DNA test checks for actual cancer cells in the stool and is done every 1 or 3 years.
- Flexible sigmoidoscopy: Your doctor inserts a little lighted tube into your rectum and lower part of the colon to check for polyps or cancer. This is done every 5 years (or every 10, along with that stool DNA test mentioned above).
- Colonoscopy: This is like the flexible sigmoidoscopy, but it checks the rectum and the whole colon. During a colonoscopy, the doctor may remove anything suspicious. This screening is done every 10 years for people at average risk. It can also be a follow-up test if something concerning is found in one of the screenings listed above.
- Virtual colonoscopy: This uses X-rays and computers to create images of your colon for the doctor to analyze. This one is done every 5 years.
The test you choose may depend on your health, risk factors and personal comfort level with getting screened. The important thing is to talk to your doctor who can help you pick one — and have it done regularly.
Recognizing the signs and symptoms of colon cancer may be tricky because they may be caused by something unrelated. That’s the nature of our finicky digestive system. It’s important to pay attention to how your gut is functioning because it might be trying to tell you something. Here’s a list of symptoms that colon cancer might cause:7
- Diarrhea, constipation or change in bowel movements
- Rectal bleeding or bloody stool
- Constant abdominal pain or cramps
- Feeling like your bowel doesn’t empty all the way
- Weakness or fatigue
- Unexplained weight loss
Keep in mind, early stages of colon cancer may likely not cause any symptoms at all. But, if any of these sounds familiar, schedule a visit with your doctor right away.
Most people have about a 4% chance of being diagnosed with colon cancer in their lifetime (men 4.4% and women 4.1%). However, the rate of diagnosis continues to drop because more people are getting screened and making lifestyle changes that lower their risk.8, 9 The list below shows which factors might increase your risk for colon cancer.10
- Poor health: Diabetes, obesity, smoking, alcohol, inactivity and diet all may play a crucial role in your chances for getting colon cancer. The good news? These are all things you can change! (Yes, you can. We know you can do it.) Talk with your doctor about lifestyle habits to help lower your risk.
- Older age: The majority of cases happen in people 50 or older.
- Race: African-Americans have a greater chance of getting colon cancer.
- Personal and family history: If you or a close family member has been diagnosed, you’re more likely to develop it (or get it again).
- Previous radiation treatment: If you’ve had radiation therapy around the abdomen, your chances may go up.
- Inflammatory intestinal conditions: Conditions like ulcerative colitis and Chron’s disease may increase your risk.
- Inherited syndromes: Certain gene mutations form syndromes that increase your risk. The most common are familial adenomatous polyposis and Lynch syndrome. Just a small number of cases are linked to these.
It’s important to know all your risk factors, even the ones you may not be able to do anything about. We kicked off this list with the factors you can change for a reason — to motivate you in taking control of your health.
A condition that’s inherited where you’re at risk for colorectal cancer and cancer in other major organs. These can include stomach, small intestine, liver, gallbladder, urinary tract, brain and skin.
There are a number of different treatment options out there. The cancer’s stage and location may help determine which treatment (or combination of treatments) may be best for you.10
- Surgery: This is the most common treatment for colon cancer. For early (and small) cancers, you might have the polyps removed during surgery or your colonoscopy. More advanced cancers that have spread might require part of your colon or surrounding lymph nodes to be removed.
- Radiation: This might be used to kill cancer cells or help shrink a big tumor before surgery (that makes it easier to remove).
- Chemotherapy: Chemo(therapy) drugs help kill cancer cells. Chemotherapy is often used after surgery that’s been done to remove advanced tumors. It helps kill any remaining cancer cells and lowers the risk of your cancer coming back.
- Immunotherapy: This approach works a little like a vaccine — but for colon cancer. It may help your body recognize and fight off cancer cells.
There’s no single right treatment approach for colon cancer. Each person’s journey is different. Be sure to have a conversation with your doctor and care team about the pros and cons of each option and do your own research so you’re comfortable with the plan you pick.
Who should I see if I'm concerned about colon cancer?
If you think you might have symptoms of colon cancer, or you’re concerned about your risk level, schedule a visit with your primary care provider (the doctor or provider you might see for your yearly physical). Bring a list of your symptoms, family history and any questions you want answered. If your doctor thinks you may have signs of colon cancer, he or she may order one or more of those tests we mentioned above. Or, you might be referred a gastroenterologist. (Your body could be telling you that your gut just needs a little TLC.) If your test results show signs of cancer, you’ll likely be referred to an oncologist to discuss further tests and treatment options.11
- Key Statistics for Colorectal Cancer cancer.org, 2021.
- Picture of the Colon webmd.com, 2020.
- What is Colorectal Cancer? cancer.org, 2021.
- Colorectal Cancer Screening cancer.org, 2021.
- What Should I Know About Screening? cdc.gov, 2021.
- Colorectal Screening Tests cancer.org, 2021.
- Colorectal Cancer Signs and Symptoms cancer.org, 2021.
- Colorectal Cancer Statistics cancer.org, 2021.
- Colon cancer- Symptoms and causes cancer.org, 2021.
- Colon cancer- Diagnosis and treatment cancer.org, 2021.
- Colon cancer- Preparing for your appointment cancer.org, 2021.