Key Points about Colorectal Adenocarcinoma

  • Colorectal adenocarcinoma is the most common type of colon and rectal cancer.
  • Doctors use biopsy, imaging tests, colonoscopy and physical exam to diagnose colorectal adenocarcinoma.
  • Treatment for colorectal adenocarcinoma may include surgery, chemotherapy, targeted therapy and/or radiation therapy.


The colorectal area refers to the colon and rectum, which make up the large intestine. Colorectal adenocarcinoma is a type of cancer that begins in the large intestine. There are multiple types of colon and rectal cancer, but colorectal adenocarcinoma is the most common type.

Colorectal adenocarcinoma causes

This condition is caused by mutations (changes) to the DNA of the large intestine cells. The two types of gene mutations that affect colorectal adenocarcinoma are:

  • Acquired gene mutations – these are gene mutations that occur during a person’s lifetime and are not passed down in families. Acquired gene mutations cause most cases of colorectal cases.
  • Inherited gene mutations – these are gene mutations that are passed down in families. These make up a small number of cases of colorectal cancer.

Colorectal adenocarcinoma risk factors

The following factors may increase your risk for developing colorectal adenocarcinoma:

  • Being a smoker
  • Being African-American
  • Being female
  • Being older than age 50
  • Drinking an excessive amount of alcohol
  • Eating a diet high in fat, low in fiber and high in red or processed meats
  • Having a family history of colorectal cancer
  • Having certain gene mutations
  • Having colon polyps
  • Having type 2 diabetes
  • Having ulcerative colitis (UC)
  • Not getting enough physical activity

Colorectal adenocarcinoma symptoms

In its early stages, most people with this condition don’t experience any symptoms. When they do occur, signs and symptoms of colorectal adenocarcinoma can include:

  • Bleeding from the rectum
  • Blood in the stool
  • Constipation or diarrhea
  • Feeling of fullness in the bowels after having a bowel movement
  • Pain in the abdomen
  • Tiredness or weakness
  • Unintentional weight loss

Colorectal adenocarcinoma diagnosis

Your oncologist may use one or more of the following tests to diagnose this condition:

  • Physical exam – your doctor will perform a complete physical exam – including asking questions about your health history, your symptoms and related risk factors.
  • Blood tests – your doctor will send a sample of your blood to the laboratory for close analysis. The lab technician checks your blood for liver, kidney, blood count and other factors that could indicate colon cancer.
  • Colonoscopy – during this test, your doctor passes a thin, flexible tube with a camera on the end through your rectum and into your colon for look for polyps (growths) or any other suspicious areas.
  • Computerized tomography (CT) scan – this type of imaging test provides a 3-D image of the inside of the body that your doctor can use to determine if there is any cancer present.
  • Biopsy – in this test, your doctor removes a biopsy (small tissue sample) from the colon. This sample is sent to the laboratory, where a specialist closely checks the biopsy for abnormalities.
  • Magnetic resonance imaging (MRI) – this type of imaging test uses high-powered magnets to create detailed images of the inside of your body. Your doctor can closely examine these images to look for any areas that could indicate cancer.
  • Ultrasound – this type of imaging test uses sound waves to create detailed images of the inside of your body. Your doctor can closely examine these images to look for any areas that could indicate cancer.

Colorectal adenocarcinoma treatment

Depending on your personal health history, the extent of the colorectal adenocarcinoma and other factors, your oncologist may recommend one or more of the following treatment options:

  • Surgery – in many cases, your doctor will recommend a surgical procedure to remove the cancerous area. The surgery may be as simple as removing a small polyp or as complex as removing a portion of the colon with cancerous cells. Your surgeon will work to preserve as much surrounding healthy tissue as possible. 
  • Chemotherapy – you may need to undergo chemotherapy to destroy any cancerous cells that couldn’t be removed surgically. During this treatment, medication is used to destroy cancerous cells. Chemotherapy can be taken via an oral (by mouth) pill or intravenously (through a vein).
  • Radiation therapy – this treatment uses high-powered energy beams to destroy cancerous cells. You may need to undergo radiation therapy to destroy any cancerous cells that couldn’t be removed surgically.
  • Targeted therapy – this treatment focuses on the molecular changes that make cancer cells grow and spread. These therapies are less likely than chemotherapy to harm healthy cells and may have fewer side effects. 

When should I seek care?

If you experience any of these symptoms, start by voicing your concerns and symptoms to your primary care provider. From there, your doctor may suggest seeing an oncologist for more specialized treatment.

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