Colon Cancer Treatment Stage by Stage

by Linda Rodgers Health Writer

Colorectal cancer (a.k.a. colon cancer) is divided into stages based on where in the colon (your large intestine) the cancer is located and how far it’s spread. “The stage of colon cancer largely dictates what treatments you're eligible for,” says Rishi Jain, M.D., an oncologist specializing in gastrointestinal tract cancers at the Fox Chase Cancer Center in Philadelphia.

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What Staging Means

“Staging involves understanding three things. First, you need to know how much the tumor is extending into the wall of the colon. Second, whether there is cancer in any of the lymph nodes by the colon. Then third, whether there is cancer outside of the colon, which is metastatic disease,” explains Leah Biller, M.D., an oncologist at Dana-Farber’s Gastrointestinal Cancer Treatment Center in Boston. To get the answers, doctors use a combination of surgical and clinical procedures, including imaging. The stage of your cancer is on a scale from 0 to 4.

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Surgery’s Role in Staging

When doctors remove the tumor, they’re able to tell how far it extends inside the colon wall. They also remove the tissue around it. “The surgeon takes out a big chunk of the colon, a piece on either side of the tumor, to make sure they get the whole thing. And we like them to get at least 12 lymph nodes all in the area of the tumor. Those get looked at by pathology to see if there’s any cancer cells in them,” explains Dr. Biller, who’s also an instructor at Harvard Medical School in Boston.

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Imaging’s Role in Staging

Doctors use a computed tomography (CT) scan of your abdomen, lungs, and pelvis to see if the cancer has spread outside the colon. “Sometimes we'll find little tiny things in the liver or in the lung and we don't know, is that cancer or is that just little tiny things that we find incidentally? And that may require more workup with a different type of imaging or a biopsy,” Dr. Biller explains. In that case, you’ll probably get an MRI or PET scan, which give doctors more detailed pictures.

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Treating Stage 0

Stage 0 is very early cancer that is many times caught during a colonoscopy, the go-to colon cancer screening test. It’s also known as carcinoma in situ and means there are abnormal cells (sometimes clumping together) in the innermost lining of the colon. Doctors usually cut out these cells during the colonoscopy, and that’s it—treatment done. The odds of Stage 0 cancer coming back are pretty low—one study put it at 1.68% after five years.

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Treating Stage 1

The cancer has spread deeper into the wall of your intestine, but not beyond it. Doctors cut out the cancer, and depending on the size of the mass, they may also remove tissue around it. Unless the cancer is found to be “high-grade” (meaning it’ll spread faster), surgery is usually all you need to treat it. Stage 1 cancer can be cured, says Dr. Jain. The 5-year survival rate is 90.2%.

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Treating Stage 2

In Stage 2, the cancer has spread through the colon wall and possibly into the tissue around it, but it hasn’t gone into the lymph nodes. Doctors will remove the tumor and the surrounding tissue. Unless you have high risk factors, you probably won’t need chemotherapy after the surgery, but if your tumor is high-grade or the cancer has spread to nearby blood vessels, chemo is warranted. Discuss this with your doctor, though: One study found chemo improved the survival rate (which, like stage 1, is about 90%) of all stage 2 patients.

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Treating Stage 3

If the colon cancer has spread to nearby lymph nodes, like those located in the large intestine, the diagnosis is stage 3. It’s treated with surgery to remove the mass and surrounding tissue, followed by chemotherapy. Sometimes, doctors will use radiation to shrink the tumor before performing surgery. Stage 3 cancer is curable, with a 5-year survival rate of roughly 72%.

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Treating Stage 4

When the cancer cells have spread to other parts of your body, like your lungs or liver, or to faraway lymph nodes like those in your groin or armpit, you have stage 4, or metastatic, cancer. The treatment is a combination of chemo and newer drugs, such as targeted therapy or immunotherapy, and sometimes surgery, depending on where the tumors are located and how big they are. The 5-year survival rate for stage 4 patients is about 15%. The goal is to prolong your life along with the quality of it, Dr. Jain says.

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Boosting the Immune Response

While stage 4 colon cancer isn’t curable, there are a number of new therapies that have been very effective for some patients, says Andrea Cercek, M.D., a medical oncologist at Memorial Sloan Kettering Cancer Center in New York City. Immunotherapy, which uses medicines to rev up the immune system’s cancer-killing ability, is an option for people whose tumors have tested positive for certain gene changes. These drugs are known as checkpoint inhibitors because they block a protein that turns off immune cells, thereby firing up the immune response.

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Personalized Drugs

Targeted drug therapy is another option for some people with Stage 4 (metastatic) cancer. Your doctor will test your tumor for specific biomarkers—including DNA, proteins, and genetic mutations—to see if you’re a candidate. One class of these drugs homes in on a protein, known as epidermal growth factor receptor (EGRF), that spurs the growth of cancer cells. The other class of meds is anti-angiogenesis drugs, which stop the development of new blood vessels feeding the cancer.

Linda Rodgers
Meet Our Writer
Linda Rodgers

Linda Rodgers is a former magazine and digital editor turned writer, focusing on health and wellness. She's written for Reader’s Digest, Working Mother, Bottom Line Health, and various other publications. When she's not writing about health, she writes about pets, education, and parenting.