The stages of colon cancer: why you need to catch it early

Colorectal cancer written in medical documents.

Colorectal cancer, or cancer that forms in the tissues of the colon and rectum, also called colon cancer, is the third most common cancer in both men and women in the United States. And while the death rate has been dropping over the past few decades, it’s still the second-leading cause of cancer-related death.

The good news is that statistically, the earlier that you catch colon cancer, the better your chances for survival.

WellTuned spoke with Dr. Daniel Cusator, a medical director for BlueCross BlueShield of Tennessee, to find out what you need to know about how colon cancer progresses. And he explains why you might want to go ahead and schedule that colonoscopy.

Stages of colon cancer

Dr. Cusator: There are five stages of colon cancer, ranging from early to advanced. Just like other cancers, the lower the stage number, the less the chance that the cancer has spread.

  • Stage 0: (also called carcinoma in situ) abnormal cells in colon wall
  • Stage I: cancerous cells in innermost layers of colon or rectum
  • Stage II: cancer through the muscular wall
  • Stage III: cancer in local lymph nodes
  • Stage IV: cancer has spread to distant lymph nodes or other parts of the body

The goal of screening is to identify the colorectal cancer at Stage 0 when it’s cured by simple removal during a colonoscopy.

Here’s why:

  • The five-year survival rate for people with localized colorectal cancer—that is, cancer that hasn’t spread beyond its original site–is 91%.
  • But only about 37% of people are diagnosed at this early stage, according to the American Society of Clinical Oncology.
  • The five-year survival rate drops to 72% when the cancer spreads to nearby lymph nodes or surrounding organs or tissues.

10 facts to know about colorectal cancer in Tennessee

Cancer screening methods

Dr. Cusator: You have several options for screening methods. But the best method is the one that you will follow through with.

The current screening options include:

  • Colonoscopy. During a colonoscopy, a doctor will insert a long flexible tube with a light and a tiny camera at the end through the anus and rectum and up into the colon. One advantage to a colonoscopy is that your doctor can go ahead and remove any polyps that are detected—and even some cancers. Unless you have certain increased risk factors, you only need to undergo a colonoscopy every 10 years.
  • Stool test. Stool tests entail analyzing a stool sample for the presence of blood. With a fecal occult blood test, you can even collect a stool sample at home, then send the sample to a lab for analysis. Most stool tests are conducted annually, but the FIT-DNA test, which looks for altered DNA in the stool, only needs to be done every three years.
  • Flexible sigmoidoscopy. A doctor uses a long, narrow, lighted tube to check for polyps inside your rectum and colon.
  • CT colonography. Also known as a virtual colonoscopy. Your doctor uses imaging tests like x-rays to produce an image of your colon on a computer screen for analysis.

Ask your doctor which colorectal cancer screening method you should choose. They can advise you on the pros and cons of each method based on your individual situation, risk factors and health plan coverage.

Know your risk

Dr. Cusator: Your risk for developing colorectal cancer goes up as you get older. In fact, age is the number one risk factor for colorectal cancer, per the National Foundation for Cancer Research. And 90% of colorectal cancers are diagnosed in people over the age of 50. That doesn’t mean you can’t get colorectal cancer when you’re younger than 50.

Experts caution that the incidence of colorectal cancer among younger adults is on the rise. The United States Preventive Services Task Force (USPSTF) makes recommendations to help prevent disease. In 2021, the USPSTF lowered the recommended age for colorectal cancer screening from age 50 to age 45.

People who have other risk factors may be advised to get screened even before they turn 45. If you know you have risk factors, discuss that with your doctor.

Other factors that can raise your risk:

  • A family history of colorectal cancers, especially in a parent, sibling or child
  • A personal history of cancer in the colon, rectum, or ovary
  • A personal history of colorectal polyps that are at least 1 cm wide
  • Inherited changes in certain genes that raise your risk for conditions such as Lynch syndrome and familial adenomatous polyposis
  • A personal history of an inflammatory bowel disease like Crohn’s disease or chronic ulcerative colitis
  • Smoking or tobacco use
  • Alcohol use
  • Obesity or being overweight
  • An unhealthy diet

If any of those risk factors sound like they apply to you, check with your doctor and discuss next steps.

“Colon cancer screenings can actually prevent colon cancer by detecting problems before they turn into cancer,” explains Dr. Cusator. “In the meantime, eating a well-balanced diet, getting regular exercise, and maintaining a healthy weight are the best ways to reduce modifiable colorectal cancer risk factors.”

More from Dr. Cusator on WellTuned.

Jennifer Larson

Jennifer Larson is Nashville-based writer and editor with nearly 20 years of experience. She specializes in health care and family issues.

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