Colorectal Cancer: What It Is, Causes, Types, Symptoms & Treatment

Colorectal cancer is one of the most common cancers in the United States.

Learn more about what colorectal cancer is, including its causes, types, symptoms, staging, treatment and survival rate.

What is colorectal cancer?

If your health care team finds cancer that started in your colon (bowel), they’ll diagnose you with colon cancer.

Cancer that starts in the rectum (the final section of bowel where stool is held before it passes out of the body) is called rectal cancer.

Colorectal cancer, the National Cancer Institute explains, is the type that starts in either your colon or your rectum.

Colorectal cancer causes

Experts aren’t sure what causes colorectal cancer. But some factors make you more likely to get this type of cancer, according to the American Cancer Society.

The risk factors include:

• Age (People age 50 and older are more likely to have colorectal cancer)
• Alcohol use
• Being overweight or obese
• Cystic fibrosis
• Diets that include a lot of red and processed meats
• Family history of polyps or colorectal cancer
• Eating meat that has been fried, broiled or grilled
• Gene mutations (changes) that are acquired, meaning they occur during your lifetime
• Gene mutations that you are born with
• A sedentary lifestyle
• Not getting enough vitamin D
• Racial and ethnic backgrounds that include American Indian and Alaskan Native people
• Tobacco use
• Type 2 diabetes

If you have a risk factor, that doesn’t automatically mean you will get colorectal cancer. And there are a few risk factors you can control.

"Some potential risk factors, like cigarette smoking and diet, are changeable,” U.S. National Institutes of Health (NIH) researcher Erikka Loftfield wrote in an article titled Lowering Your Cancer Risk.

Types of colorectal cancer

There are different types of cancer of the colon and the rectum. Your health care provider may mention one or more of these types:

• Adenocarcinomas
• Carcinoid tumors
• Gastrointestinal stromal tumors (GISTs)
• Lymphomas
• Sarcomas

Colorectal cancer symptoms

The signs and symptoms of colorectal cancer include:

• Abdominal pain, cramping
• Bloating
• Blood in the stool (either bright red or dark)
• Blood from the rectum (bright red)
• Constipation (that’s new and lasts more than a few days)
• Diarrhea (that’s new and lasts more than a few days)
• Fatigue (feeling very tired)
• Feeling like the bowel doesn’t completely empty
• Gas pain
• Narrow stool (that’s new and lasts more than a few days)
• Vomiting
• Weakness
• Weight loss (not on purpose)

Colorectal cancer screening

During a cancer screening, your health care provider checks to see if you have symptoms or a family history of cancer. According to the National Cancer Institute, the screening may include a:

• Blood test
• Colonoscopy, an internal examination done under sedation using a long, flexible tube called a colonoscope with a camera at one end
• Computed tomography (CT or CAT) scan
• Digital rectal exam (Your doctor will insert a gloved finger into your rectum to feel for anything abnormal)
• Genetic test and genetic counseling, if needed
• Proctoscopy, a procedure to examine the inside of the rectum and anus
• Stool sample (to check for blood and other issues related to colorectal cancer)
• Ultrasound

The American Cancer Society recommends regular colon cancer screenings starting at age 45.

Colorectal cancer diagnosis

If your screening finds issues, your health care team may get a biopsy, in which tissue is removed from your rectum and/or colon for analysis. This study can confirm if there are cancer cells.

The National Cancer Institute notes that if you’re then diagnosed with colorectal cancer, your doctor will also tell you what stage you’re in. The stage is how advanced your cancer is.

Colorectal cancer staging

The stage of your colorectal cancer is determined by how far the cancer cells have spread. A higher number means the cancer has spread more.

The stage will help your doctor choose the best treatment for you, according to the American Cancer Society.

Colorectal cancer treatments

There are seven types of treatments for colorectal cancer, according to the National Cancer Institute. They are:

• Surgery
• Radiofrequency ablation, a minimally invasive technique that shrinks the size of tumors
• Cryosurgery, a treatment that uses extreme cold to destroy cancer cells and abnormal tissue
• Chemotherapy, a drug treatment that uses powerful chemicals to kill cancer cells
• Radiation therapy, which kills cancer cells by destroying their DNA
• Targeted therapy, a type of treatment that uses drugs or other substances to precisely identify and attack cancer cells
• Immunotherapy, which uses the person's own immune system to fight the cancer

Your health care team will determine the best type of treatment based on the stage of your colorectal cancer.

Colorectal cancer medication

What medication you take for your colorectal cancer depends on the location where the cancer began. Medications for colon cancer may not be the same as the medications for rectal cancer.

Colorectal cancer surgery

The National Cancer Institute says surgery is the most common treatment for all stages of colon cancer. There are three types of surgeries:

• Local excision, removing a suspicious growth along with some tissue around it
• Surgery to remove some or all of the colon and reconnect healthy sections
• Resection of the colon with colostomy, an opening that provides a new path for waste material outside the body

Talk to your health care team about the risks and benefits of each type.

Colorectal cancer survival rate

The NIH SEER program reports that 65% of people diagnosed with colorectal cancer in the United States survive for five or more years.

Living with colorectal cancer

If you’re living with colorectal cancer, you are not alone. In the United States, more than 4% of men and women will, at some point during their lives, be diagnosed with this type of cancer.

Resources

American Cancer Society: Colorectal cancer

National Cancer Institute: Colorectal Cancer Treatment -Patient Version

National Cancer Institute: Screening Tests to Detect Colorectal Cancer and Polyps

National Cancer Institute, Surveillance, Epidemiology and End Results Program (SEER): Cancer Stat Facts: Colorectal Cancer

NIH News in Health: Lowering Your Cancer Risk