What is colon cancer?
Colon cancer is cancer that starts in the inside lining of the colon, which is part of your large intestine. Not counting skin cancers, it’s the third most diagnosed cancer today. Because they are similar, colon and rectal cancer are often grouped and called colorectal cancer.
This type of cancer is highly preventable and treatable when caught early. According to data from the CDC, there are more than 150,000 new cases of colorectal cancer each year in the United States. However, this number has decreased over the last two decades—most likely due to increased compliance with screening and polyp removal.
You have options if you have colon cancer risk factors or a new colon cancer diagnosis. Our locations offer complete services to care for you, from screenings to second opinions to innovative cancer care.
Symptoms of colon cancer
Especially in the early stages of colon cancer, it’s possible to have no symptoms at all. The symptoms of colon cancer can also mimic other digestive conditions, such as infections, hemorrhoids and inflammatory bowel disease.
That’s why it’s essential to listen to your body and talk to your doctor if you have ongoing symptoms or notice something feels off with your digestive health. Check-in with your physician if you have any of the following symptoms:
- Bowel habit changes, including diarrhea or constipation
- Narrow or ribbon-like stools that last for more than a few days
- Rectal bleeding, visible blood in the stool or dark stools
- Cramping or gnawing stomach pain
- Decreased appetite
- Vomiting
- Unintended weight loss
- Weakness and fatigue
- Continuing to feel that you cannot empty your bowels
In the later stages of colon cancer, you’re more likely to have symptoms like weight loss, swelling and pain in your abdomen. If colon cancer spreads, it can also cause symptoms in other areas of your body, such as the lungs or liver. Your healthcare team can help you get to the source of your symptoms.
Causes of colon cancer
Colon cancer happens when abnormal cells in the colon’s lining divide and multiply. Doctors don’t fully understand why this occurs in some people, and there isn’t one leading cause of colon cancer. Many factors combine to decide your risk of developing the disease, from family history to medical conditions to lifestyle choices.
However, we do know that most colon cancers start from polyps. By finding and removing pre-cancerous polyps through routine colon cancer screening, doctors have the potential to stop colon cancer before it ever starts.
Colon cancer risk factors
While you can make some lifestyle choices to reduce your risk of colon cancer, other factors may not be in your control. For example, medical conditions, genetics, age and ethnicity all play a role in your personal risk.
One of the most important steps to protect yourself from colon cancer is knowing your risk factors and talking with your doctor about the right colon cancer screenings for you. If you have a high risk of colon cancer, your care team will walk you through your options so that you can take action to reduce your risk.
-
Lifestyle choices that are risk factors for colon cancer
- Smoking: All tobacco use, including smoking, increases your risk of colon cancer. Stopping smoking reduces your risk of colon cancer—and many other types of cancer.
- Excessive alcohol use: Heavy drinking is linked to a higher risk. Men should limit alcohol to two drinks a day, while women should only have up to one drink daily.
- Obesity: Those with obesity have a higher chance of developing colon cancer. Take steps to maintain a healthy weight to reduce your colon cancer risk.
- Low-fiber, high-fat diet: A diet low in fiber and high in fat and calories, especially red or processed meats, may increase your risk of colon cancer. To prevent colon cancer, focus on high-fiber, low-fat choices.
- Not exercising: Physical inactivity is associated with an increased risk. Regular exercise may help you reduce your risk.
-
Medical conditions that increase colon cancer risk
- Inflammatory bowel disease: Chronic inflammation in the colon due to inflammatory bowel disease, including ulcerative colitis and Crohn’s disease, can increase the risk of cell changes that may lead to colon cancer.
- Inherited genetic syndromes: Some genetic syndromes, such as Lynch syndrome and familial adenomatous polyposis, cause a high lifetime cancer risk. For example, the National Institutes of Health reports that Lynch syndrome is the cause of about 2-4% of all cases of colon cancer.
- Family history of colon cancer or other cancers: People with a strong family history of colon cancer or polyps in a first-degree relative, especially in a parent or sibling before age 45 or in two first-degree relatives of any age, have an increased risk for colon cancer.
- Personal or family history of polyps: If you previously had colon polyps or have a close relative with an advanced or large polyp, you’re at an increased risk.
- Diabetes: People with Type 2 diabetes risk colon cancer more than those without diabetes.
-
Other risk factors
- Age: Most people with colon cancer are over 45, but it can occur at any age.
- Race and ethnicity: African Americans have the highest risk for colon cancer of all racial groups in the United States. The ethnic group with the highest risk worldwide is Jews of Eastern descent (Ashkenazi Jews).
Hereditary colon cancer
It’s estimated about 5-10% of all cases of colon cancer are hereditary colon cancer. This means a person inherits a specific genetic mutation that makes them much more likely to develop colon cancer.
Several genetic mutations and syndromes have been linked to colon cancer, but researchers continue to look into other genetic causes of the disease. The most common hereditary conditions currently connected to a high risk of colon cancer are Lynch syndrome and familial adenomatous polyposis.
If you have a strong family history of colon cancer or a blood relative diagnosed with a genetic condition linked to colon cancer, talk with your doctor about genetic counseling. A genetic counselor can guide your next steps, including genetic testing and preventive care, based on your risk factors and history.
How colon cancer is diagnosed
You have several options to help screen for and diagnose colon cancer. Your care team will decide on the right option based on your symptoms, risk factors, family and medical history, and more.
Early diagnosis of colon cancer is vital to provide you with the most options for your care and the highest recovery rate. When cancer is caught in its earliest stages, the survival rate is more than 90% at five years.
Especially if you have symptoms, a colonoscopy is the most commonly used test for colon cancer. However, blood tests, stool tests and imaging tests also give your healthcare team valuable information about your colon health and help with diagnosis and treatment planning.
Colonoscopy
A colonoscopy uses a tube with a light and a small camera to let your doctor look at the inside of your entire colon. During a colonoscopy, your provider may take tissue samples or remove polyps to help diagnose cancer.
Sigmoidoscopy
A sigmoidoscopy, including flexible sigmoidoscopy, uses a small tube and camera to view the inside of the colon and look for signs of cancer. While colonoscopy looks at the whole colon, sigmoidoscopy only looks at the bottom portion of the colon.
Fecal testing
Fecal or stool testing allows you to take a sample—or multiple samples—of your stool at home and then send them to a lab to look for hidden blood or DNA that might signal cancer. The most common colon cancer stool tests include Guaiac-based fecal occult blood tests, fecal immunochemical tests and stool DNA tests.
Blood tests
Your doctor may order blood tests such as a complete blood count, comprehensive metabolic panel or CEA assay. These could help identify abnormal levels of cells or antigens in your blood or rule out other conditions.
CT colonoscopy
Sometimes called a virtual colonoscopy, this procedure uses computed tomography (CT) to create images of your colon. These images are then reviewed to look for polyps or cancer in the colon.
X-ray
To get a closer look at your colon and look for cancer, your doctor may use a barium enema. This moving X-ray, or fluoroscopy, procedure injects barium into the colon through the rectum to coat it and create images.
Types of colon cancer
Most of the time, colon cancer begins in the cells that make up the colon’s inner lining. But there are other types of colon cancer, too. Some rare types of colon cancer start in the blood vessels, muscles, lymph cells or hormone-producing cells.
Understanding the type of colon cancer you have is important because it will guide your care. Your healthcare team will tailor your treatment options based on the type and stage of the cancer.
-
Colorectal adenocarcinoma
By far, the most common type of colon cancer is colorectal adenocarcinoma. More than 95% of people with colon cancer have this type. Adenocarcinoma can start in the cells that line many different organs. In this case, it starts in the lining inside the colon. Often, adenocarcinomas begin as polyps before they turn into cancer.
-
Gastrointestinal carcinoid tumors
Gastrointestinal carcinoid tumors start in special hormone-producing cells in the large intestine. This type of cancer often doesn’t cause symptoms initially and may grow slowly. Carcinoid tumors account for only 1% of all colon cancer cases. They’re more common in the small intestine.
-
Gastrointestinal stromal tumors
Gastrointestinal stromal tumors (GIST) start in specialized cells in the wall of the digestive tract called the interstitial cells of Cajal. They can be noncancerous at first, but many turn into cancer. While more common in other parts of the digestive system, this type of cancer is rare in the colon. Only a few thousand cases of GIST are diagnosed each year.
-
Primary colorectal lymphomas
In rare cases, a type of non-Hodgkin's lymphoma may start in the colon. This type of lymphoma affects the lymphocytes—a white blood cell that works as part of the immune system. Primary colorectal lymphomas make up less than 1% of all colon cancers.
-
Leiomyosarcomas
Leiomyosarcoma is a rare type of cancer that starts in the colon—accounting for only 0.1% of cases. It begins in the smooth muscle layers of the colon. Like other types of colon cancer, leiomyosarcomas may not cause symptoms in the early stages.
Stages of colon cancer
After colon cancer diagnosis, staging determines the most suitable action and treatment options.
Colon cancer is categorized into four stages, ranging from 0 to 4, where stage 0 represents the earliest precancerous phase and stage 4 indicates the most advanced stage.
Understanding the significance of each colon cancer stage and the typical treatment plans for both stages and substages can provide valuable insights into the best approach to managing the disease.
Colon cancer treatment
Treatment options for colon cancer continue to improve, especially for cancers caught before they can spread to distant locations in the body. Your care team will create a colon cancer treatment plan based on your colon cancer stage, type, health history and individual needs.
Many treatment plans include some type of surgery to remove as much colon cancer as possible. But your care team may also recommend chemotherapy, radiation, targeted therapies or immunotherapy options. Sometimes, multiple treatments are used together to care for you. In some cases, you may have the option to be a part of a clinical trial as part of your colon cancer care.
Surgery
Surgery is a common treatment in all stages of colon cancer. The goal of surgery is to remove all or part of the cancerous cells. Many of our care locations offer advanced, minimally invasive options, including laparoscopy or robotic-assisted surgery, which use smaller incisions to help speed up recovery.
Some surgical options include:
- Polypectomy, a procedure done through endoscopy (colonoscopy) to remove a cancerous polyp
- Colectomy, a surgery to remove a section of the colon affected by cancer or all of the colon
- Colectomy with colostomy, a procedure that removes all or part of the colon and connects the top of the colon to an opening in the abdomen and a bag to collect stool, which can be temporary or permanent
Chemotherapy
Chemotherapy drugs are sometimes used to treat colon cancer by shrinking or destroying cancer cells. This treatment option is often used with surgery and is most common in stage 3 and stage 4 colon cancer.
Radiation
In some cases, radiation therapy is used to treat colon cancer. It destroys cancer with targeted high-energy rays. Radiation therapy is less common than chemotherapy or surgery in colon cancer and is often used in the later stages of the condition.
Targeted therapy
This type of treatment targets specific genes or proteins in cancer cells to prevent them from continuing to grow or multiply. One of the most common targeted therapies is monoclonal antibodies.
Immunotherapy
Immunotherapy is an innovative treatment for colon cancer that uses the body’s immune system to destroy cancer. Cells are often modified in the lab and then infused into the blood to help fight cancer better.
Colon cancer prevention
The best way to fight colon cancer is to stop it from developing. With today’s colon cancer screening tools, many cases of colon cancer are preventable. You can also reduce your risk through healthy lifestyle choices, knowing your family history and seeking care for digestive symptoms.
Some actions you can take to help prevent colon cancer include:
- Get routine colon cancer screenings
- Take proactive steps if you have a family history or conditions that increase your risk
- Focus on a high-fiber, low-fat diet and reduce the amount of red and processed meats
- Maintain a healthy weight
- Quit smoking and tobacco products
- Limit the amount of alcohol you consume
- Stay physically active
- Manage health conditions like diabetes
Screening for colon cancer
For people with an average risk, the U.S. Preventive Services Task Force recommends starting colon cancer screening at the age of 45. The screening test you choose, from stool tests to colonoscopy, will determine how often you should be screened.
In general, screening options include:
- High sensitivity gFOBT stool test: every year
- FIT stool test: every year
- sDNA-FIT stool test: every one to three years
- Colonoscopy: every ten years
- Virtual colonoscopy: every five years
- Flexible sigmoidoscopy: every five years
- Flexible sigmoidoscopy: every ten years when used with FIT every year
If you have risk factors for colon cancer, talk with your doctor about when and how often you should have a colon cancer screening.
Our locations near you
We help you get care at a location that fits your needs. We offer several locations for your care, including colon cancer screening, diagnosis and treatment in North and Central Texas.
Frequently asked questions
-
Can colon cancer be cured?
In most cases, yes. Especially when colon cancer is found in the early stages, it is a very treatable and sometimes curable type of cancer. If colon cancer is localized, meaning it has stayed in the colon, surgery is often the only treatment needed.
-
Where is colon cancer pain?
The most common place to have pain or discomfort caused by colon cancer is the lower abdomen. However, colon cancer may not cause pain at all. It’s possible to have colon cancer without any symptoms.
-
Can colon cancer cause back pain?
It’s rare for colon cancer to cause back pain, but it’s possible. You may have back pain as a symptom of colon cancer if the tumor causes pressure on the spine or spreads to the spine. Back pain can also be a side effect of colon cancer treatment.
-
Where does colon cancer tend to metastasize to?
Some of the most common places colon cancer might metastasize—or spread—are the liver, lungs, brain, abdominal cavity and distant lymph nodes.
-
Will colon cancer show on CT scan?
Yes, CT scans can show signs of colon cancer and look for signs that the cancer may have spread to other areas of the body. A CT colonography scan is sometimes used to screen for colon cancer but may not detect smaller polyps.