Your Practical Guide to Preparing for Radiation Therapy

Why Do I Need Radiation Therapy?

Radiation therapy uses targeted forms of energy to disrupt the growth and reproduction of cancer cells. It is used to prevent breast cancer recurrences after surgery or to treat cancer in areas of cancer spread (metastases), such as the ribs or spine.

Early Effects of Radiation Therapy: Fatigue

Radiation therapy commonly causes fatigue. Your body uses a great deal of energy to absorb the radiation and to repair the normal tissues affected by your treatments. Many people describe it as being similar to the tiredness you might experience after spending a long day in the sun at the beach or by the pool.

Early Effects of Radiation Therapy: Your Skin

Skin irritation during radiation therapy is very common and usually develops gradually over the course of treatment. Many people describe the sensation as similar to a sunburn, with symptoms such as redness, warmth, tingling, tenderness, or a hot feeling in the treated area.

Radiation Dermatitis

Radiation dermatitis usually starts 1 to 3 weeks after you begin radiation therapy.

Your radiation team may prescribe a steroid cream to apply to the treated skin twice each day. Be sure to follow their instructions carefully, even if your skin does not appear irritated or inflamed. The reason your skin is doing well is likely because the steroid cream is helping to control inflammation, so do not stop using the cream unless directed by your radiation oncologist or nurse.

Protecting Your Skin

Some common-sense ways to protect your skin during radiation and as you are healing are:

Wear loose outfits: Choose soft, loose clothing that will not rub against your breast or chest.

Exercise and Activity Adjustments

Reduce friction under your arm: Put your hand in your pocket while walking or hiking to keep your arm from rubbing against your irritated armpit skin. If you are on a treadmill, rest your hand on the handlebars or safety rail while you walk.

What is Radiation Simulation (Treatment Planning)?

A radiation simulation (or “sim”) is an important planning visit before your treatments begin. During this appointment, your radiation therapists carefully position your body and may create custom supports to ensure you are in the same position each day. A CT scan (Computed Tomography) is then taken to map out the exact area that needs treatment. A CT machine looks like a donut, which you can see in the picture here.

What is “The Vault?”

A radiation treatment vault is a special room where radiation therapy is safely delivered. The walls, floor, and ceiling are made very thick — often with concrete or other protective materials — to keep the radiation contained inside the room. Vaults are large, high-tech spaces that are carefully designed to keep you safe while delivering your treatment as precisely as possible.

What can I expect during a radiation treatment?

You will likely be told that the actual radiation treatment only takes about 5 minutes, but realistically, it takes a bit longer to deliver.

Deep Inspiration Breath Hold (DIBH) — What to Expect

Why is Prone Radiation Sometimes Used?

If your anatomy allows you to receive radiation while lying on your belly, your breast tissues will hang down and away from your heart and lungs while the radiation is being delivered. Because of this breast positioning, a deep breath inspiration hold is not typically needed. CT scan imaging and planning will be necessary before your radiation oncologist can decide if you can safely receive radiation therapy in this position.

Late Effects of Radiation Therapy

Late or long-term side effects often begin several months after treatment, typically around 3–4 months after radiation is completed. Late effects of radiation therapy may include:

Permanent skin changes to the radiated areas. (these may take years to develop) This occurs because the blood capillaries become permanently dilated from radiation damage, like spider veins.

Bonus Information for those who are curious:

Internal Radiation (Brachytherapy)

Radiation is placed inside the body, near or within the treatment area

Often used after surgery
Involves the placement of radioactive sources (seeds, ribbons, or capsules) directly inside or next to a tumor, allowing for a high, targeted dose of radiation while minimizing damage to surrounding healthy tissue.
May be delivered in a hospital or as an outpatient procedure depending on your specific treatment plan.

Intraoperative Radiation Therapy (IORT)

A specialized form of internal brachytherapy radiation delivered during surgery
Administered directly into the tumor cavity immediately after the cancer is removed
Although delivered during surgery, the radiation source originates from outside the body