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Radiation therapy uses high-energy rays or particles to kill cancer cells.

When is radiation therapy used?

Depending on the stage of the non-small cell lung cancer (NSCLC) and other factors, radiation therapy might be used:

• As the main treatment (sometimes along with chemotherapy), especially if the lung tumor can’t be removed because of its size or location, if a person isn’t healthy enough for surgery, or if a person doesn’t want surgery
• After surgery (alone or along with chemotherapy) to try to kill any small areas of cancer that surgery might have missed
• Before surgery (usually along with chemotherapy) to try to shrink a lung tumor to make it easier to operate on
• To treat cancer spread to other areas, such as the brain or bone
• To relieve (palliate) symptoms of advanced NSCLC, such as pain, bleeding, trouble swallowing, cough, or problems caused by spread to other organs such as the brain

Types of radiation therapy used for NSCLC

Different types of radiation therapy can be used to treat NSCLC. There are 3 main types:

• External beam radiation therapy
• Brachytherapy (internal radiation therapy)
• Proton therapy

External beam radiation therapy

External beam radiation therapy (EBRT) focuses radiation from outside the body onto the cancer. This is the type of radiation therapy most often used to treat NSCLC or its spread to other organs.

Treatment is much like getting an x-ray, but the radiation dose is stronger. The procedure itself is painless, and each treatment lasts only a few minutes. Most often, radiation treatments to the lungs are given 5 days a week for 5 to 7 weeks, but this can vary based on the type of EBRT and the reason it’s being given.

Newer EBRT techniques have been shown to help doctors treat lung cancers more accurately while lowering the radiation exposure to nearby healthy tissues. These include:

• Stereotactic body radiation therapy (SBRT), also known as stereotactic ablative radiotherapy (SABR), is most often used to treat early-stage lung cancers when surgery isn’t an option due to a person’s health or in people who don’t want surgery. It might also be considered for tumors that have limited spread to other parts of the body, such as the brain or adrenal gland.

Instead of giving a small dose of radiation each day for several weeks, SBRT uses very focused beams of high-dose radiation given in fewer (usually 1 to 5) treatments. Several beams are aimed at the tumor from different angles. To target the radiation precisely, you are put in a specially designed body frame for each treatment. This reduces the movement of the lung tumor during breathing.

• Three-dimensional conformal radiation therapy (3D-CRT) uses special computers to precisely map the tumor’s location. Radiation beams are then shaped and aimed at the tumor(s) from several directions, which makes it less likely to damage normal tissues. Intensity modulated radiation therapy (IMRT) is a form of 3D therapy. Along with shaping the beams and aiming them at the tumor from several angles, the strength of the beams can be adjusted to limit the dose reaching nearby normal tissues. This technique is used most often if tumors are near important structures such as the spinal cord.

A variation of IMRT is called volumetric modulated arc therapy (VMAT). It uses a machine that delivers radiation quickly as it rotates once around the body. This allows each treatment to be given over just a few minutes.

• Four-dimensional conformal radiation therapy (4DCT) shows where the tumor is in relation to other structures during each part of the breathing cycle, as opposed to just giving a “snapshot” of a point in time, like a standard CT does. This technique might also be used to help show if a tumor is attached to or invading important structures in the chest, which could help doctors determine if a patient might be eligible for surgery. 
• Stereotactic radiosurgery (SRS) isn't really surgery, but a type of stereotactic radiation therapy that is given in only one session. It can sometimes be used instead of or along with surgery for single tumors that have spread to the brain. In one version of this treatment, a machine focuses about 200 beams of radiation on the tumor from different angles over a few minutes to hours. Your head is kept in the same position with a rigid frame. In another version, a linear accelerator (a machine that creates radiation) that is controlled by a computer moves around your head to deliver radiation to the tumor from many different angles. These treatments can be repeated if needed.

For more detailed descriptions of these procedures, see External Beam Radiation Therapy.

Brachytherapy (internal radiation therapy)

In people with NSCLC, brachytherapy is sometimes used to shrink tumors in the airway to relieve symptoms.

The doctor places a small source of radioactive material (often in the form of small pellets) directly into the cancer or into the airway next to the cancer. This is usually done through a bronchoscope, but it may also be done during surgery. The radiation travels only a short distance from the source, limiting the effects on surrounding healthy tissues. The radiation source is usually removed after a short time. Less often, small radioactive “seeds” are left in place permanently, and the radiation gets weaker over several weeks.

Proton therapy

In people with NSCLC, especially Stage III, proton therapy may be an option.  Proton therapy is a type of radiation that uses protons rather than x-rays. A proton is a positively charged particle, which can be targeted specifically to the tumor.  Compared to x-rays, proton therapy beams are less likely to damage surrounding organs, such as the heart and esophagus (tube we use to swallow). This form of radiation therapy continues to be studied, and is offered in most specialized lung cancer treatment centers. 

Possible side effects of radiation therapy for NSCLC

If you are going to get radiation therapy, it’s important to ask your doctor about the possible side effects so you know what to expect. Common side effects depend on where the radiation is aimed and can include:

• Fatigue
• Nausea and vomiting
• Loss of appetite and weight loss
• Skin changes in the area being treated, which can range from mild redness to blistering and peeling
• Hair loss where the radiation enters the body

Often these go away after treatment. When radiation is given with chemotherapy, the side effects may be worse.

Radiation therapy to the chest may damage your lungs and cause a cough, problems breathing, and shortness of breath. These usually improve after treatment is over, although sometimes they may not go away completely.

Your esophagus, which is in the middle of your chest, may be exposed to radiation, which could cause a sore throat and trouble swallowing during treatment. This might make it hard to eat anything other than soft foods or liquids for a while. This also often improves after treatment is finished.

Radiation therapy to large areas of the brain can sometimes cause memory loss, headaches, or trouble thinking. Usually these symptoms are minor compared with those caused by cancer that has spread to the brain, but they can affect your quality of life.