Radiation Therapy: Colorectal Cancer Treatment and Recovery

Colorectal cancer refers to the group of cancers that impact the colon or rectum. It’s the third most common type of cancer worldwide with nearly 2 million new diagnoses in 2020. A person’s lifetime risk of developing colorectal cancer is about 1 in 23 for men and 1 in 25 for women.

Preventive screenings are crucial — diagnosing and treating colorectal cancer in its early stages gives you the best chance of recovery. We’re highlighting a less-commonly-used but effective colorectal cancer treatment — radiation therapy — including why to use it over other treatment paths, different types of radiation therapy and what recovery from this treatment type is like.

Keep reading for invaluable help from our expert, radiation oncologist Carlos Lopez, MD.

What Is Radiation Therapy?

Dr. Lopez explains, “Radiation therapy, also known as radiotherapy, is a type of cancer treatment. It uses beams of intense energy to kill cancer cells and most often uses X-rays.” Other types of radiation therapy exist, including proton radiation.

Modern methods of radiation are exact. They aim beams directly at the cancer while protecting healthy tissues from high doses of radiation. Radiation therapy can be provided inside or outside of your body.

Why Use Radiation Therapy?

Radiation therapy, chemotherapy and surgery are the standard interventions in the multidisciplinary treatment of colorectal cancer.

Radiation therapy can be used to treat most types of cancer. In fact, more than half of all people with cancer will receive radiation therapy as part of their treatment. Radiation therapy also may be used to treat some conditions that aren't cancerous, including non-cancerous, or benign, tumors.

Radiation Therapy for Colon Cancer

It's not common to use radiation therapy to treat colon cancer, but it may be used in the following situations:

• After surgery, if the cancer has attached to an internal organ or the lining of the belly (abdomen). If this happens, the surgeon can’t be sure that all the cancer has been removed. Radiation therapy may be used to try to kill any cancer cells that may have been left behind.
• During surgery, right to the area where the cancer was, to kill any cancer cells that may be left behind. This is called intraoperative radiation therapy or IORT.
• Along with chemo to help control cancer if a person is not healthy enough for surgery.
• To ease symptoms if advanced colon cancer is causing intestinal blockage, bleeding, or pain.
• To help treat colon cancer that has spread to other areas, such as the bones, lungs, or brain.

Radiation Therapy for Rectal Cancer

For rectal cancer, radiation therapy is a more common treatment and may be used:

• Either before or after surgery, often along with chemotherapy, to help keep the cancer from coming back. Many doctors now favor giving radiation therapy before surgery, as it may make it easier to remove the cancer, especially if the cancer's size and/or location might make surgery difficult. This is called neoadjuvant treatment. Giving chemoradiation before surgery can also help lower the chances of damaging the sphincter muscles in the rectum when surgery is done. In either case, nearby lymph nodes are usually treated too.
• During surgery, right to the area where the tumor was, to kill any rectal cancer cells that may be left behind. This is called intraoperative radiation therapy or IORT.
• With or without chemo to help control rectal cancer if a person is not healthy enough for surgery or to ease symptoms if advanced rectal cancer is causing intestinal blockage, bleeding or pain.
• More recently, as definitive therapy in combination with chemotherapy in selected cases allowing to avoid surgery, an approach called non-operative management.
• In some cases, to retreat rectal tumors that come back in the pelvis after radiation was given.
• To help treat rectal cancer that has spread to other areas, such as the bones, lungs or brain.

Types of Radiation Therapy

Different types of radiation therapy can be used to treat colorectal cancers. Let’s take a look at some of them in more detail.

External-Beam Radiation Therapy (EBRT)

EBRT is the type of radiation therapy used most often for people with colorectal cancer. The radiation is focused on the cancer from a machine outside the body. It's similar to getting an X-ray, but the radiation is more concentrated.

Internal Radiation Therapy (Brachytherapy)

Brachytherapy might be used to treat some colorectal cancers, but more research is needed to understand when to use brachytherapy and how to best use it.

For this treatment, a radioactive source is placed inside your rectum next to or inside the tumor, allowing the radiation to reach the rectum without passing through the skin and other tissues of the abdomen. That makes it less likely to damage healthy nearby tissues.

Endocavitary Radiation Therapy

For this treatment, a small balloon-like device is placed into the rectum to deliver high-intensity radiation for a few minutes. This is typically done in about four treatments, with about two weeks between each treatment. This can allow some patients avoid major surgery and a colostomy.

This treatment is used for some small rectal cancers, or in cases where radiation was already given in the pelvic area and the rectal cancer has come back. Sometimes external-beam radiation therapy is also provided.

Interstitial Brachytherapy

For this treatment, needles are placed into the rectum and right into the tumor. Small pellets of radioactive material are then put into the needles for several minutes. The radiation travels only a short distance, limiting the harmful effects on nearby healthy tissues.

Interstitial Brachytherapy is sometimes used to treat people with rectal cancer who aren’t healthy enough for surgery or have cancer that has returned. It can be done a few times a week for a couple of weeks, but it can also be a one-time procedure.

What is Recovering From Radiation Therapy Like?

If you're a candidate for radiation therapy, ask your doctor about the possible short- and long-term side effects so that you know what to expect. Possible side effects of radiation therapy for colorectal cancer can include:

• Bladder irritation
• Bowel incontinence
• Fatigue
• Nausea
• Rectal irritation, which can cause diarrhea, painful bowel movements or blood in the stool
• Scarring, fibrosis (stiffening), and adhesions that cause the tissues in the treated area to stick to each other
• Sexual side effects (erectile dysfunction in men and vaginal irritation in women)
• Skin irritation at the site where radiation beams were aimed, which can range from redness to blistering and peeling
• Wound healing problems, if radiation was given before surgery

Dr. Lopez says, “Most side effects should gradually improve after your radiation therapy treatment is over, but some problems may not go away completely. If you notice any side effects, talk to your physician so steps can be taken to reduce or relieve them.”

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To learn more about what we have to offer, visit us here. You deserve to feel whole.