7 Colorectal Cancer Treatments and Therapies, Explained by Doctors

After being diagnosed with colon or rectal cancer, a doctor may suggest one or multiple treatments.

Colon and rectal cancers—known collectively as colorectal cancer—are on the rise in the US among people under 50 years old, according to the American Cancer Society. In 2020, it was estimated that 12% of all colorectal cancer diagnoses would be in those under 50, amounting to about 18,000 cases.

Conversely, in the over-50 crowd, the diagnosis rates of colorectal cancer have actually decreased, thanks in large part to more people getting the recommended screening tests to find the disease at its earliest stages—a huge factor in whether or not someone will survive a colorectal cancer diagnosis.

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Regardless of the age, when someone is given a colorectal cancer diagnosis, a team of doctors will often work together to come up with the best possible treatment plan for the patient. "We use a multidisciplinary team to treat cancer: surgeons, medical oncologists, radiation oncologists," Ashwani Rajput, MD, a colon cancer surgeon and director of the Johns Hopkins Kimmel Cancer Center for the National Capital Region, tells Health. "The treatments are really changing and evolving and very much individualized to the patient."

In that case, each specialist might suggest a different method of treatment and, often, they'll work together to attack the cancer through multiple types of treatment. Here's what you need to know about each type of colorectal cancer treatment available, and when they're most likely to be used.

What is colorectal cancer?

First, a recap: Colorectal cancer, like any cancer, begins from changes in one cell or a small group of cells in the body. "Cancer is an uncontrolled growth of a certain cell type and can be found in any tissue in your body," Richard Whelan, MD, chief of colon and rectal surgery at Northwell Health, tells Health.

Colon and rectal cancers are found in the digestive system. The colon is the main part of a person's large intestine and stretches nearly five feet long. The rectum is a section of tissue only a few inches long at the end of the large intestine.

What's different about colorectal cancers is that they grow out of polyps, which are small bundles of tissue that bulge out of the organ itself. "There's this normal progression from the normal, to the polyp, to a scary looking polyp or what we would call "high grade dysplasia" which is kind of pre-cancer, and then turning into a cancer," Dr. Rajput says.

Colorectal cancer is extremely preventable if the polyps are caught early. But if they aren't, they can puncture the intestine, causing bleeding or obstruction of the waste moving through the digestive tract, and travel from the colon or rectum to other parts of the body. Typically, colorectal cancer that spreads goes to the liver or the lungs, but once the cancer gets into the bloodstream or the lymphatic system (a network of tissues, vessels, and organs), it can spread anywhere. When it spreads, doctors classify it as metastatic colorectal cancer.

How is colorectal cancer treated?

According to Dr. Rajput, there are three main ways colorectal cancer are treated: surgery, chemotherapy, and radiation. The National Institutes of Health classify seven different types of colorectal treatments overall, adding four more treatment options as offshoot treatments in addition to the main three: radiofrequency ablation, cryosurgery, targeted therapy, and immunotherapy—all offered depending on the stage of a patient's cancer.


More often than not, colorectal cancer treatment will include surgery, Dr. Whelan says. "The vast majority of patients are treated by taking out a piece of the large bowel, and then the surgeon will try to put the two pieces back together," he says.

How invasive the surgery is depends on the stage the cancer is in. If colorectal cancer is caught in early stages, a surgeon may take out only a small amount of the colon through a process called local excision, according to the NIH. During a local incision, the surgeon will likely get to the colon through the rectum, putting a tube that includes a cutting tool up through the rectum so that they don't have to cut through the abdominal wall. After a local incision, doctors will follow the patient very carefully to ensure the cancer doesn't come back, Dr. Rajput says.

If the cancer isn't caught until later stages, the surgeon will perform what's called a partial colectomy, meaning that they'll cut out the cancerous portion of the colon as well as a small amount of healthy tissue around it. Usually, the doctor will also take out lymph nodes near the colon in order to test whether the cancer has metastasized.

In most cases, colon resections don't cause problems with the function of the bowel later. If they have to take out a section of the colon, surgeons will perform an anastomosis, meaning that they'll sew the two remaining, healthy parts of the colon together. The remainder of the colon then makes up for what was taken out, Dr. Rajput says. "So, most of the time you don't have to worry about getting a colostomy bag, although those are usually temporary, he says.

A colostomy bag is a bag placed around an opening surgeons make on the outside of the body (called a stoma) so that digestive waste can pass outside of the body if the two healthy sections of colon can't be sewn together. In emergency colon surgeries, a temporary bag may be used to allow the colon to heal. However, if the doctor needs to remove the entirety of the lower colon, the bag may be permanent.

Permanent colostomy bags are more common when the colorectal cancer is found in the rectum, Dr. Rajput says. "I often say that it's like real estate, it's 'location, location, location'," he says.

When patients have cancer very low in the rectum or cancer that involves the sphincter complex — which includes a ring of muscle that controls bowel movements — surgeons have to remove the sphincter in order to get control of the tumor. Without a sphincter, a person couldn't control when they poop and so surgeons will attach a permanent colostomy bag to collect waste.


Sometimes, chemotherapy can be used on its own to treat colorectal cancer, but it's often used in combination with surgery, Dr. Whelan says. "The general trend is that if you've got metastatic disease that you cannot remove entirely, you rely on chemotherapy primarily before you do surgery," he says.

Chemotherapy uses drugs to stop cancer cells from growing, either by killing them or by stopping them from dividing, according to the NIH. Chemotherapy drugs can be taken by mouth or by an injection (known as systemic chemotherapy), or by an oncologist who will target the drugs directly to a specific area of the body (known as regional chemotherapy).

Often, doctors will suggest chemotherapy for patients who have cancer low in the rectum in an attempt to save the rectum and avoid a colostomy bag. "What we're finding with rectal preservation is that there's a subset of patients who have an excellent response with chemotherapy and radiation and we don't find any evidence of tumor when they come back," Dr. Rajput says. Then, the doctor will do something called "watchful waiting," essentially keeping a close eye on the cancer in case it comes back.

At times, chemotherapy will also be used after surgery as a way to ensure any leftover cancer cells are killed before they can spread. "It's a very small subset of these cells that can set up shop elsewhere, but that's what we're trying to kill," Dr. Rajput says.

Radiation therapy

The treatment options for rectal cancer are a little different than those offered for colon cancer, Dr. Rajput says, and that's mostly because rectal cancer treatment includes radiation therapy.

Radiation therapy uses high-energy x-rays or other radiation to kill cancer cells or stop them from growing, according to the NIH. Radiation therapy can be either internal or external. Interal radiation is given through a radioactive substance concealed inside needles, seeds, wires, or catheters that a doctor will place directly into or near the cancer. External radiation uses a machine to send x-rays or other radiation toward the cancerous area of the body.

Typically, external radiation is used as a palliative therapy once cancer has reached an incurable stage in order to help patients feel better. Internal, targeted radiation is used to kill the cancer from the inside and, as Dr. Rajput said, is often used in combination with chemotherapy.

Radiofrequency ablation

Radiofrequency ablation isn't used to treat the primary tumor, Dr. Rajput says. Instead, it can sometimes be used to treat colorectal metastases, which are tumors or abnormal cell growth in areas where the primary cancer has spread to.

During radiofrequency ablation, doctors will use a probe that has tiny electrodes that kill cancer cells through electrical energy and heat, according to the NIH. A radiologist will insert the probe directly through the skin or through an incision in the abdomen, using imaging technology to guide a thin needle into the cancer tissue.

Because it's so targeted, radiofrequency ablation is typically used to treat just one (usually particularly difficult) spot of cancer rather than the cancer as a whole, according to the Mayo Clinic.


Like with radiofrequency ablation, cryosurgery is a directed treatment used to destroy one tumor rather than treating the cancer overall. Cryosurgery uses a "cryoprobe" — a hollow instrument that circulates very cold gas such as liquid nitrogen or argon gas, according to the NIH. During the procedure, a doctor will use an ultrasound or MRI to guide the cryoprobe to the tumor. Once it touches the tumor, the cryoprobe forms a ball of ice that freezes the tissue, killing the cancer cells. After the cryosurgery, the frozen tissue will thaw and be absorbed by the body.

Cryosurgery is also used externally to treat tumors that have grown on the outside of the body, like those on the skin. For external cryotherapy, liquid nitrogen is applied directly to the tumor with a cotton swab or a spray, according to the NIH.

Targeted therapy

Targeted therapy falls under the broad category of chemotherapy, Dr. Rajput says. Medical oncologists will use targeted therapy to identify and attack specific cancer cells. "Targeted therapy uses newer drugs that target receptors or signaling pathways that are critical for tumor growth," Dr. Rajput says.

There are two types of targeted therapies used to treat colon cancer, according to the NIH. One, called monoclonal antibodies, are lab-made immune system proteins that can attach to cancer cells or cells that help cancer grow and then kill the cells, block their growth, or keep them from spreading.

The other, called angiogenesis inhibitors, stops new blood vessels from growing in the tumor, which stops the tumor itself from growing.


Immunotherapy is also part of medical oncologists' toolbag in treating colorectal cancer, Dr. Rajput says. As it implies, immunotherapy uses the patient's immune system to fight cancer. Medical oncologists will use substances, such as certain proteins, made either in the body or in the lab to boost, direct, or restore the body's immune system in hopes that it will target the invading cancer cells, according to the NIH.

Though these treatment options can give anyone diagnosed with colorectal cancer a great fighting chance against the it, the best offense against the disease is still a good defense. That means scheduling and sticking to the recommended colorectal cancer screenings starting at age 45, like having a colonoscopy every 10 years, for those without an increased risk of the disease. Colorectal cancer is largely preventable, Dr. Rajput says, and while the screenings for the disease can seem off-putting at first, they can (and do) save lives.

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