Colorectal Cancer Types, Symptoms, and Risks

Colorectal cancers are the third most commonly diagnosed cancers in men and women in the United States.

Doctors diagnosed about 95,000 cases of colon cancer and 39,000 cases of rectal cancer in the U.S. in 2016.

These cancers are also the third leading cause of cancer-related deaths. But, more people are surviving the disease now than in the past.

What Is Colorectal Cancer?

Colorectal cancer occurs when malignant cells form in the tissues of the colon and rectum.

The colon — also called the large intestine — has four parts:

  • Ascending colon
  • Descending colon
  • Sigmoid colon
  • Transverse colon

It's responsible for the last stages of digestion.

The sigmoid colon connects to the rectum and continues the process of removing waste from the body.

Colorectal cancer can occur in any section of the large intestine or in the rectum.

UPMC Hillman Cancer Center offers state-of-the-art, evidence-based treatment for people with colorectal cancer.

Our team includes experts from many specialties including:

Types of Colorectal Cancer

Based on where the cancer begins, most people treated for colorectal cancer have either colon cancer or rectal cancer.

Other less common types of colorectal cancers that form in different types of tissues include:

  • Carcinoid tumor
  • Gastrointestinal stromal tumor
  • Lymphoma
  • Small cell carcinoma

Colorectal Cancer Early Signs and Symptoms

Some early warnings may include:

  • Blood (bright red or very dark) in stool.
  • Change in bowel habits.
  • Diarrhea, constipation, or feeling the bowels don't fully empty.
  • Fatigue.
  • Frequent gas pain, bloating, fullness, or cramps.
  • Stools that are narrower than usual.
  • Vomiting.
  • Weight loss for no known reason.

Call your doctor if you have any of these symptoms. Even if the cause isn't colorectal cancer, they might be signs of other health problems that need treatment.

Colorectal Cancer Risk Factors

Most people have about a five percent chance of getting colorectal cancer.

Certain factors can increase your risk, such as:

  • Age over 50.
  • Being African American.
  • Being male.
  • Family history of colorectal cancer.
  • Genetic syndromes:
    • Familial adenomatous polyposis.
    • Gardner syndrome.
    • Hereditary nonpolyposis colorectal cancer (HNPCC, or Lynch syndrome).
    • Peutz-Jeghers syndrome.
  • History of other cancers, including uterine and ovarian cancer.
  • Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis.
  • Obesity.
  • Polyps.
  • Poor nutrition (a diet heavy in red meat and processed meats).
  • Smoking.

Early Stages of Colorectal Cancer

Colorectal cancers often begin as noncancerous polyps.

Without treatment, these polyps can become cancer that grows deeper into the tissue. Cancer can also spread to other parts of the body.

Doctors stage colorectal cancer based on:

  • How deep the tumor has grown into the lining of the colon or rectum.
  • Whether the cancer cells have spread to nearby lymph nodes.
  • Whether the cancer has spread beyond the main site.

Staging can be a complex process that may require:

  • A colonoscopy to see inside the colon.
  • A biopsy to remove some of the tissue to view under a microscope.
  • Blood tests and other imaging scans.

Colorectal staging in general ranges from stage 0 to stage IV:

  • Stage 0 — the cells are only in the inner lining and haven't penetrated deeper. Doctors refer to this stage as “cancer in situ.”
  • Stage I — cancer is deeper in the muscle layer of the organ but hasn't spread to lymph nodes.
  • Stage II — this stage can be A, B, or C. It depends on how far through the lining of the organ the tumor has grown. The cancer still hasn't spread to any lymph nodes.
  • Stage III — this stage can be A, B, or C. At this stage, the cancer has grown deeper in the organ lining. It has also spread to surrounding lymph nodes.
  • Stage IV — the cancer has spread (metastasized) to other organs in the body. Cancer can spread through tissue, the lymph system, or blood.

Colon Cancer Screening

When caught early, doctors successfully treat up to 90 percent of people with colon cancer. This means that regular colon cancer screening is crucial.

A colonoscopy detects polyps in the lining of the colon or rectum. It's the only procedure that can find and remove polyps before they become cancerous.

During a colonoscopy, you will receive sedation. Your doctor inserts a tube in the rectum and colon to look for polyps or cancer.

People over the age of 50 should have regular screenings with a colonoscopy every 10 years. African Americans should begin receiving screenings at age 45.

If you have any risk factors for colorectal cancer, talk to your doctor about when to start screening and how often.

If you have cancer or have concerns about a colonoscopy, our experts can help.

At UPMC Hillman CancerCenter, we:

Even if you've received colorectal cancer screening or care at another center, UPMC Hillman Cancer Center has treatment options for you.

Contact Us About Colon, Rectal, and Gastrointestinal Cancer 

To learn more about Colorectal and Gastrointestinal Cancers or to make an appointment, you can: