Stage 3 Colon Cancer

An illustration of colon cancer.
An illustration of colon cancer. SEBASTIAN KAULITZK/Getty Images

There are five stages of colon cancer (0-4). In general, the earlier the stage, the easier the cancer is to treat and the better the outlook is for survival.

Stage 3 colon cancer, also known as stage III, used to be known as Duke's C colon cancer. Stage 3 tumors are divided into three groups, from least advanced to most advanced. The least advanced is called stage 3A (formerly Duke's C1), the one in the middle is stage 3B (formerly Duke's C2), and the most advanced is stage 3C (formerly Duke's C3).

Think Like a Tumor

To understand your tumor, it helps to think like one. You open your eyes and find yourself in a fleshy tunnel (a colon) and the only thing you know is this: You must dig out of that tunnel. Escape. Spread.

The ground you're standing on is the first layer of the colon, the mucosa. If you dig a little, you'll pass through a thin muscle layer and run into the submucosa. Dig a little more and you'll hit a thick muscle layer, then another major muscle layer. Keep digging and you'll reach the outermost layer of the colon, the serosa. Along the way, you'll be hoping to hit a blood vessel or lymph node, since infiltrating either will help you move faster.

That's what you were born to do, and that's what you'll try to do until someone stops you.

Differences Between Stages 3A, 3B, and 3C

When discovered at stage 3A, colon cancer has reached the middle layers of the colon and spread to as many as three nearby lymph nodes.

In stage 3B, cancer is present in as many as three nearby lymph nodes and:

  • has spread beyond the middle layers of the colon; or
  • has worked its way into nearby tissues; or
  • has extended through the colon wall into nearby organs (such as the bladder or ovaries) and/or stretched into the peritoneum – tissue that covers most of the organs in your abdomen.

    What differentiates stage 3C colon cancer from stages 3A and 3B are the number of lymph nodes involved. A stage 3 tumor means cancer has been found in four or more nearby lymph nodes.

    Treatment for Stage 3 Colon Cancer

    Treatment for stage 3 colon cancer generally consists of surgical removal, or resection, of the tumor, followed by chemotherapy. In a surgical resection, a surgeon removes the part of the colon affected by the tumor and joins the remaining healthy sections together to form one long, healthy piece.

    The standard chemotherapy regimen used to be six months of treatment with 5-FU and leucovorin, but that "cocktail" was developed decades ago and is seldom used anymore. If your doctor recommends the "old standard," a second opinion would be a good idea because there are many new chemotherapy regimens available for stage 3 colon cancer. For more information, please read Colon Cancer Treatment Options.

    Survival Rate for Stage 3 Colon Cancer

    A lot of things can influence colon cancer survival rates. Stage is a major factor, but tumor location, country of residence, and factors such as age, sex, and exercise habits have also been shown to impact survival. For example, tumors in the right side of the colon are often caught later because symptoms take longer to emerge, and in countries where early screening is relatively uncommon, tumors are caught later.

    Studies have also found that exercise may increase colon cancer survival rates.

    According to the American Cancer Society, 83 percent of people with stage 3A colon cancer are still alive five years after their diagnosis. The survival rates for stage 3B (64 percent) and stage 3C (44 percent) are less encouraging. However, it's important to remember that survival rates are generalizations and your individual chances of survival may be quite different. Also, survival data reflects what has happened in the past. With all the new chemotherapy drugs available, it's possible that today's survival rate for stage 3 colon cancer is significantly higher.


    Cancer Facts and Figures 2005. American Cancer Society. Accessed 14 Mar. 2007.

    Colon Cancer PDQ: Treatment: Stages of Colon Cancer. National Cancer Institute. 20 May 2005. Accessed 14 Mar. 2007.

    Colon Cancer PDQ: Treatment: Stage III Colon Cancer. National Cancer Institute. 5 Mar. 2007. Accessed 14 Mar. 2007.

    Detailed Guide: Colon and Rectum Cancer: How is Colorectal Cancer Staged? American Cancer Society. 22 Feb. 2007. Accessed 14 Mar. 2007.

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