Metastatic Colorectal Cancer

Overview

The colorectal area refers to the colon and rectum, which make up the large intestine. Colorectal cancer is a type of cancer that begins in the large intestine. When colorectal cancer spreads beyond its initial site, this is known as metastatic colorectal cancer.

The most common places to which colorectal cancer spreads are:

• Bones
• Brain
• Liver
• Lungs
• Spinal cord

Metastatic colorectal cancer causes

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

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

Metastatic colorectal cancer risk factors

The following factors may increase your risk for developing metastatic colorectal cancer:

• 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

Metastatic colorectal cancer symptoms

Symptoms specific to metastatic colorectal cancer depend on the site of the cancer spread.

If colorectal cancer has metastasized to the liver, you may experience:

• Jaundice (yellowing of the whites of the eyes or skin)
• Unusual swelling

If colorectal cancer has metastasized to the lung, you may experience:

• Shortness of breath

If colorectal cancer has metastasized to the bone, you may experience:

• Bone fractures
• Bone pain

If colorectal cancer has metastasized to the brain, you may experience:

• Dizziness
• Headache
• Seizures

Metastatic colorectal cancer 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, symptoms and related risk factors.
• 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.
• 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 to look for polyps (growths) or any other suspicious areas.
• Computerized tomography (CT) scan – this type of imaging test provides a 3D image of the inside of the body that your doctor can use to determine if there is any cancer present.
• 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.
• Positron emission tomography (PET) scan – your doctor may use this type of imaging test to check for colorectal cancer that may have spread to the brain.
• 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.

Metastatic colorectal cancer treatment

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

• Surgery – in some 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.