Cancer Center

Radiation Therapy

Also known as: DXT, Radiation Oncology, Radiotherapy, XRT

At high doses, radiation has proven to shrink tumors and treat pain and other problems caused by the tumor by damaging the cancer cell's DNA. Radiation therapy (radiotherapy) refers to this treatment method. Radiation therapy can either damage DNA directly or create charged particles called free radicals within the cells that can in turn damage the DNA. Cancer cells whose DNA is damaged beyond repair stop dividing and die. When the damaged cells die, they are broken down and eliminated by the body’s natural processes. Radiotherapy is often given before, during, or after oncological surgery as a more complete regimen.

There are two main types of radiation therapy, external beam and internal.

External beam radiation therapy comes from a Linear Accelerator machine (LINAC) that aims radiation at the area of malignancy. The machine sends radiation to that part of the body from many directions. This therapy treats only a specific part of the body.

Internal radiation therapy is a treatment in which a source of radiation, liquid or solid, is put inside the body. Internal radiation therapy with a solid source is called brachytherapy. In this type of treatment, radiation in the form of seeds, ribbons, or capsules is placed in your body in or near the cancer.

Potential Side Effects


Fatigue is one of the most common side effects experienced during cancer treatment. It is important to manage fatigue as it can contribute to feelings of depression, lack of appetite, or increased pain.

Hair Loss

Will I lose my hair? This is a common question amongst patients considering cancer treatment. While some patients see this as a minor side effect, others consider it very daunting. Most cancer treatments, including chemotherapy and radiation therapy, damage rapidly dividing cancer cells, but can also damage rapidly dividing healthy cells. Hair follicles happen to be one such normal rapidly dividing group of cells in our bodies.


Pain is one of the most common and feared symptoms of cancer or its treatment. If not adequately managed, pain can have a tremendous impact on your quality of life. It is important to remember that you should always notify your oncologist if you have pain or if it is increasing. Pain is usually your body’s way of telling you that something is wrong, so do not ignore it or assume that it is a necessary part of your treatment.

Skin Changes

One of the most common side effects of radiation therapy can be skin changes. These occur because radiation has to pass through your skin in order to treat the area of cancer. Sometimes your skin is the target for radiation therapy. Most skin changes are manageable and temporary.

Nausea and Vomiting

Nausea can be a very debilitating side effect if you receive radiation to your stomach or upper abdomen. In some cases, you can experience nausea if you are receiving treatment to your brain. In either instance, be sure to alert the radiation oncology staff if you become nauseous during your treatment course.

Oral Side Effects

If you receive radiation therapy to your head or neck region, you may experience oral side effects. One of the most common oral side effects is dry mouth. Radiation can reduce the functioning of some of the salivary glands around your mouth and can thus reduce saliva. Not only can this be uncomfortable, it can lead to loss of appetite in the short-term, and possibly increased dental problems in the long-term.

Bowel Changes

Diarrhea can be a common side effect of radiation therapy directed to the abdomen or pelvis. It is important to control diarrhea so that you do not develop dehydration, rectal pain, or rectal bleeding.

Urinary Changes

For patients who receive radiation therapy to the pelvis, changes in urination can occur. Often this does not happen until the third or fourth week during treatment, but if radiation irritates the bladder, a patient can experience pain with urination, frequency, urgency, incontinence, or rarely, bleeding.

Sexual and Reproductive Side Effects

Women receiving radiation therapy to the pelvis may have vaginal side effects. Dryness, itching, and redness are common and manageable. Be sure to let your oncologist know of any of these changes. Depending upon the dose and target of the radiation, you may experience temporary, if not permanent, reduction in ovarian function, which can contribute to vaginal changes. Some women may experience hot flashes as their hormone functioning declines. Often these symptoms do improve after radiation therapy.

Men receiving radiation therapy may experience erectile dysfunction. Ejaculation can also be more painful and slightly bloody. Be sure to talk with your oncologist regarding continuing sexual activity during your treatment if you are being treated to the pelvis.