What is Stage 0 Colon Cancer?

An Overview

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Illustration by Donna Myers

There are five stages of colon cancer (0-4). This staging system reflects where cancer went when no one was looking. In general, the earlier the stage, the easier the cancer is to treat.

Stage 0 colon cancer is the earliest stage possible and is also called carcinoma in situ. "Carcinoma" refers to cancer that starts in epithelial tissue and "in situ" means original position or place.

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 spread faster.

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

Treatment for Stage 0 Colon Cancer

When discovered at stage 0, colon cancer hasn't moved from where it started. It's still restricted to the innermost lining of the colon.

That's good news because it usually makes treatment a lot easier.

Stage 0 colon cancer can often be removed with a colonoscope, the same instrument used during a colonoscopy. Sometimes cancer must be surgically removed, either by removing the tumor itself along with a margin of healthy tissue (to be on the safe side) or, for larger tumors, via surgical resection.

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.

Survival Rate for Stage 0 Colon Cancer

A lot of things can influence colon cancer survival rates. The stage is a major factor, but tumor location and country of residence have also been shown to impact survival. For example, tumors in the right 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. In general, more than 96% of people with stage 0 colon cancer are still alive five years after their diagnosis. 


Cancer Facts and Figures 2007. American Cancer Society. 

Colon Cancer PDQ: Treatment: Stages of Colon Cancer. National Cancer Institute. 

Colon Cancer PDQ: Treatment: Stage 0 Colon Cancer. National Cancer Institute. 10 Apr 2008. 

Detailed Guide: Colon and Rectum Cancer: How is Colorectal Cancer Staged? American Cancer Society. 5 Mar 2008. 

Five-Year Survival Rates: Colon and Rectum. National Cancer Institute's Physician Data Query System. Jul. 2002.

Haruhiko Shida, Kanako Ban, Masao Matsumoto, Kozo Masuda, Tomohiro Imanari, Takehisa Machida, Takashi Yamamoto and Tohru Inoue. "Asymptomatic Colorectal Cancer Detected by Screening." Diseases of the Colon and Rectum 39.10 (Oct 1996): 1130-1135. SpringerLink.