If radiation therapy has been recommended to treat your cancer, understanding what happens during radiation therapy and what you can expect after your first radiation treatment is important. Rocky Mountain Cancer Centers provides the most advanced radiation therapy treatments to thousands of patients every year throughout Colorado.

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What to Expect During Cancer Radiation Treatments

Continue reading below to learn more about what will happen during your radiation treatment for cancer or jump directly to the section that interests you the most by clicking on one of the questions:

What can I expect at my first radiation treatment appointment?

What to expect during radiation treatment for cancer depends on whether you are having external beam radiation therapy or internal radiation therapy, also called high-dose-rate (HDR) brachytherapy.

Your first radiation therapy appointment won’t include any actual radiation therapy. Instead, you’ll come in for a CT scan, which is used to help plan your radiation therapy. You will be positioned as you would during treatment — usually lying flat on your back — and scans will be taken of the area of the body that will be treated. You also will have tiny permanent marks (sometimes referred to as “tattoos” although they look more like a freckle) that will guide the targeting of the radiation therapy during treatment. This appointment takes about 30 minutes.

When will I start getting radiation therapy?

After you leave your first appointment with your radiation oncologist, they will use your scans to map out the exact location of the cancer within your body as well as noting the location of any surrounding healthy organs that need to be avoided during treatment. Computer modeling is then used to simulate the dose of radiation that will be delivered to the tumor during treatment, and the model is reviewed before your treatment begins. This process can take up to two weeks before you return for your first actual radiation therapy treatment.

When your treatment plan is developed, it will outline whether you will be receiving radiation therapy before, during, or after other treatments. Once you are ready to begin radiation therapy, you can usually be seen within one to two days at Rocky Mountain Cancers Centers.

What can I expect if I am receiving external beam radiation therapy?

External beam radiation treatment for cancer is typically administered every day, Monday through Friday, for five to eight weeks. About two weeks after your first radiation therapy appointment when you have the simulation scan, you’ll begin your treatments.

Each visit will be relatively short, lasting between 15 and 30 minutes. Most of that time will be spent lying on a table while the radiation therapist gets the equipment set up around you.

At Rocky Mountain Cancer Centers, we utilize image-guided radiation therapy, or IGRT. During each visit, new X-rays or low-dose CT scans of your body will be made and compared with the initial scan to determine if the tumor has moved — even by just a hair’s distance — and the radiation is adjusted accordingly.

Our dosimetrist check and calibrate our equipment daily and the equipment will not run if it is not calibrated correctly. All of this is done to ensure your safety and the effectiveness of treatment.

You will be asked to lie still for the actual treatment, which will last only a few minutes. The treatment itself is painless and is similar to getting an X-ray. You may hear clicking and whirring sounds during the treatment as the machine positions itself. During the treatment, the radiation therapist will be in a small room adjacent to your treatment room and watching you at all times. You will be able to communicate with your radiation therapist via intercom and should feel free to ask to stop if you feel sick or scared.

What can I expect if I am receiving internal radiation treatment for cancer?

Sessions for internal radiation therapy last longer than external beam radiation treatments, but there are fewer of them. Internal radiation therapy for cancer may be completed in one session or a series of three to five sessions about a week apart.

During internal radiation therapy, you will be given local anesthetic to numb the area being treated. A catheter or catheters — small tubes sometimes called ports or applicators — will be placed at the site of the tumor. Radioactive material is then delivered directly to the tumor through the catheters. The radiation therapy comes in many forms, including pellets, seeds, ribbons, wires, needles, capsules, balloons, or tubes. Depending on the type of radioactive material used, it will be left in place for only a couple of minutes and then removed or it may be left in permanently. Radioactive material that is left in permanently gradually wears off over the course of a few weeks until it no longer gives off radiation.

What side effects can I expect after radiation therapy?

How you feel after your first radiation treatment for cancer will depend on the type of treatment you had, the location of your cancer, and other characteristics that are unique to you. In many cases, you will not experience any side effects initially, but may experience some after multiple treatments as the therapy has a cumulative effect.

If you had internal radiation, you may experience soreness or tenderness where the catheter was inserted, and you likely will experience some degree of fatigue. You also may have side effects from any medication you were given during the treatment.

If you had external beam radiation, you may experience skin changes and fatigue following your initial treatment, or you may not have any radiation therapy side effects at all. Some people don’t develop side effects from external radiation until they’ve had several treatments.

Who will oversee my radiation therapy?

A doctor who specializes in using radiation to treat cancer — called a radiation oncologist — will oversee your radiation therapy. If you are having more than one type of treatment, your radiation oncologist will work closely with the rest of your cancer team to coordinate your care. Your radiation oncologist also communicates with your primary physician about your treatment plan, your progress, and any follow-up care that may be needed.

In addition to your radiation oncologist, other team members involved in administering your treatment include:

  • Radiation physicist: Calibrates radiation equipment and ensures it delivers the proper amount of radiation as prescribed by your radiation oncologist.
  • Dosimetrist: Uses computer imaging to create a radiation delivery plan based on the location of the tumor.
  • Radiation therapist: Positions you for treatment and operates radiation equipment.
  • Radiation therapy nurse: Educates you on radiation therapy, assesses your response to treatment and helps you manage any side effects that you experience.

How often will I need radiation therapy? And how many radiation treatments will I need?

Radiation therapy treatment schedules vary widely based on:

  • Type and location of cancer
  • The goal of your treatment: whether it is to rid your body of cancer, slow the cancer’s growth and progression, or ease the symptoms of your cancer
  • Type of radiation therapy used

Most external beam radiation, when used to shrink a tumor before surgery, is administered five days a week for five to eight weeks. Fewer treatments may be used if the goal is easing cancer-related symptoms.

Internal radiation (brachytherapy) is typically administered over the course of a few weeks with at least a week in between each treatment.

Will I have other treatments in addition to radiation therapy?

In some cases, radiation therapy will be the only treatment needed to treat a cancer, but often it is used in conjunction with other treatments, such as surgery, chemotherapy, immunotherapy, or some combination.

  • Radiation therapy used as preoperative therapy to shrink a tumor that will then be removed surgically is referred to as neoadjuvant therapy.
  • When radiation is administered at the same time as chemotherapy or immunotherapy, it’s called concurrent treatment.
  • Radiation therapy used as a treatment after surgery or chemotherapy is called adjuvant therapy. Its goal is to kill off any cancer cells that may have been left behind to reduce the chances of recurrence.