Everything You Need to Know about Colon Cancer (Colorectal Cancer)

There are several types of colon cancer. These vary based on the different types of cancerous cells and where they’re located in the digestive tract.

The most common type of colon cancer starts from adenocarcinomas, according to the ACS. Adenocarcinomas form within the cells that make mucus in either the colon or rectum.

Less commonly, colon cancers are caused by other types of tumors, such as:

• lymphomas
• carcinoids
• sarcomas
• gastrointestinal stromal tumors

Doctors use staging as a general guideline to help them determine how far along the cancer is. This could help them develop the best treatment plan and better predict your long-term outlook.

Stage 0 colon cancer is the earliest stage, and stage 4 is the most advanced stage.

Here’s how the stages are defined:

• Stage 0: Also known as carcinoma in situ, this stage involves abnormal cells that are only in the inner lining of the colon.
• Stage 1: The cancer has penetrated the lining, or mucosa, of the colon and may have grown into the muscle layer. It hasn’t spread to nearby lymph nodes or other parts of the body.
• Stage 2: The cancer has spread to the walls of the colon or through the walls to nearby tissues, but hasn’t affected the lymph nodes.
• Stage 3: The cancer has moved to the lymph nodes but not to other parts of the body.
• Stage 4: The cancer has spread to other distant organs, such as the liver or lungs.

Learn more about the stages of colon cancer.

You might not experience colon cancer symptoms at all, especially in the early stages.

If you do experience symptoms of colon cancer, they may include:

• constipation
• diarrhea
• blood in the stool
• changes in stool color
• changes in stool shape, such as narrowed stool
• bleeding from the rectum
• unintentional weight loss
• abdominal pain
• excessive fatigue
• the feeling that your bowel won’t completely empty (tenesmus)

It’s important to note that many of these symptoms may also be caused by other, less serious, conditions.

As such, it’s a good idea to see a doctor if you’ve had any of these symptoms for 3 weeks or more. You and the doctor can discuss your symptoms and decide if colon cancer screening is appropriate.

An early diagnosis of colon cancer gives you the best chance of curing it.

Since colon cancer often has no symptoms during the early stages, it’s often caught during routine screenings like colonoscopy.

The U.S. Preventive Service Task Force (USPSTF) and the ACS recommend starting colon cancer screening at age 45 years.

A doctor will start by getting information about your medical and family history.

They’ll also perform a physical exam. They may press on your abdomen or perform a rectal exam to determine whether lumps or polyps are present.

A variety of other tests are recommended at different yearly intervals for the screening of colon cancer, including:

• Fecal tests: Guaiac-based fecal occult blood test (gFOBT) and fecal immunochemical test (FIT) are recommended every 1 year.
• Sigmoidoscopy: Every 5 years.
• Virtual colonoscopy: Every 5 years.
• Colonoscopy: Every 10 years.

The Shield™ Blood Test by Guardant Health was approved by the Food and Drug Administration (FDA) in July 2024 for the screening of colorectal cancer.

A healthcare professional may recommend more frequent screening if you have a higher risk of developing colon cancer.

Learn more about the tests used for colon cancer detection and diagnosis.

Treatment for colon cancer will depend on several factors, such as the stage and type of cancer, and whether it’s spread to other parts of your body.

In stages 0, 1, and 2 of colon cancer, it’s often possible for a surgeon to remove cancerous polyps through surgery. If the polyp hasn’t attached to the wall of the bowels, you’ll likely have an excellent outlook.

If your cancer has metastasized, you may require other types of treatment, such as:

• colostomy
• chemotherapy
• ablation therapy
• targeted therapy
• immunotherapy

Learn more about the treatment options for colon cancer.

The exact causes of colon cancer are still unknown, but researchers have identified several factors that may increase your risk of developing colon cancer.

Genetics

Colon cancer may be caused by genetic mutations that can either be inherited or acquired. These mutations don’t guarantee you’ll develop colon cancer, but they do increase your chances.

Some genetic conditions associated with colon cancer include:

• familial adenomatous polyposis (FAP)
• Gardner’s syndrome
• Lynch syndrome
• cystic fibrosis

Some mutations may cause abnormal cells to accumulate in the colon lining, forming polyps. These are small, benign growths. However, untreated polyps can become cancerous. Removing these growths through surgery can be a preventive measure.

Learn more about the association between genetics and colon cancer.

Risk factors you can’t change

Some factors that increase your risk of developing colon cancer can’t be changed. For instance, your age, ethnicity, and family health history can all impact your risk of colon cancer.

Risk factors you can’t control include:

• being over age 50 years
• a prior history of colon polyps
• a prior history of bowel diseases
• a family history of colorectal cancer
• having certain genetic syndromes, such as familial adenomatous polyposis (FAP)
• having certain health conditions, such as inflammatory bowel disease (IBD)
• having previously had certain medical procedures, such as abdominal radiation and gallbladder removal
• being of African or Ashkenazi Jewish descent

Learn more about the causes and risk factors of colon cancer.

Certain risk factors for colon cancer, such as family history and age, aren’t preventable.

However, certain lifestyle factors that may contribute to colon cancer are preventable, and changing them might help lower your overall risk of developing this disease.

You can reduce your risk by:

• avoiding processed meats, such as hot dogs and deli meats
• eating more plant-based foods
• decreasing dietary fat and red meat
• exercising daily
• maintaining a moderate weight, especially if you have obesity or overweight
• quitting smoking, if you smoke
• reducing alcohol consumption, if you drink
• decreasing stress
• managing preexisting diabetes

Getting a colonoscopy or other cancer screenings when you turn 45 years old could help detect colon cancer. This is important, as early diagnosis and treatment could help prevent further complications.

It can be alarming and stressful to receive a diagnosis like colon cancer. Fortunately, colon cancer is treatable, especially when detected early.

The life expectancy for colon cancer is provided as a 5-year life expectancy. This compares how likely a person with colon cancer is to be alive 5 years after receiving their diagnosis compared to people without colon cancer.

Below are the 5-year survival rates for colorectal cancer, provided by the ACS:

It’s important to note that survival rates are continuing to increase as new cancer treatments are being developed.

That said, the ACS notes that colorectal cancer cases have risen by 1.3% among younger people between 2008 and 2017.

Can colon cancer be cured?

If colon cancer is diagnosed in the early stages, surgery may be able to completely remove the cancerous polyp.

Does colon cancer spread fast?

The progression of colon cancer varies for each person. However, the ACS notes that colon cancer usually takes years to develop and spread. Early detection and treatment are key to preventing further spreading and complications.

How bad is stage 1 colon cancer?

Many people don’t experience symptoms of colon cancer during stage 1. However, it’s possible to experience changes in your bowel habits, rectal bleeding, fatigue, and unexplained weight loss. It’s important to see a doctor if you experience these symptoms.

Colon cancer is a type of cancer that begins in the colon.

In the early stages, you may not experience any symptoms of colon cancer, which makes it hard to diagnose.

However, regular screening could help catch colon cancer early, leading to prompt treatment to reduce complications.