Radiation therapy is often part of the treatment of lung cancer. Both small-cell and non-small cell lung cancers are frequently treated with radiation therapy, which is often combined with chemotherapy and/or surgery.

High-energy radiation rays directed towards the body will break DNA inside cells. This causes the cells to die or stop dividing, which can control the disease and shrink the tumors.

When Is Radiation Used For Lung Cancer?

Depending upon the type and stage of your lung cancer, you might have radiation therapy at different times during your course of treatment. Your healthcare providers might consider radiation:

  • Before surgery: Radiation may decrease the tumor size, which makes the surgical procedure less complicated and more likely to be successful.
  • After surgery: The operative area is treated with radiation to treat any remaining cancer cells that may be present but undetectable on scans.
  • As an opportunity to cure cancer: With early-stage lung cancer, radiation may be as successful as surgery for offering a strong chance of long-term survival. Your healthcare providers may hesitate to use the designation “cured,” though, since there is always the possibility of lung cancer recurring.
  • To treat lung cancer: Radiation can prevent the growth of cancer cells in the lung, nearby lymph nodes, or areas where cancer has metastasized (such as the brain).
  • As palliative care: In some cases, radiation may be used to relieve symptoms and reduce pain by eliminating cancer cells and shrinking tumors that are causing discomfort.
  • As prevention: Radiation can lower the risk of recurrence or spread. In small-cell lung cancer, radiation therapy to the brain is sometimes used to kill any cells that might have spread to the brain but are not detected by imaging. This is called prophylactic cranial irradiation (PCI).

Types of Radiation

There are several techniques for radiation used in cancer treatment. For lung cancer, radiation options include external beam radiotherapy (EBRT), which is directed from outside the body, and internal radiation, in which radioactive materials are placed directly inside the lung cancer tumor.

When lung cancer spreads to the brain or another area of the body, sometimes only one or a few metastases are detected. This is called oligometastases. In these instances, certain types of radiation therapy have helped people gain long-term control over the disease.

Both methods halt the body’s production of cancer cells, which normally multiply faster and more frequently than normal cells. Healthy cells can also be affected by radiation exposure and this can cause side effects.

External Beam Radiotherapy (EBRT)

EBRT is the most commonly used radiation for lung cancer and involves high-dose radiation emitted from a machine outside the body.

Types of EBRT used for treating lung cancer include:

Conventional (Two-Dimensional) Radiation Therapy

This was, historically, the only local treatment alternative for early-stage lung cancer patients with inoperable tumors.

It lacks the detailed anatomical views now available with three-dimensional computed tomography (CT) technology, so this older form of radiation does not allow for optimal accuracy and may result in poor outcomes.

Three-Dimensional Conformal Radiation Therapy (3D-CRT)

This therapy improves on conventional therapy by allowing the technician to see all sides of the tumor. Radiation can be more specifically directed from different directions to match the shape of the tumor.

This method is still imperfect, however, because it relies to some degree on trial and error to get the radiation beams aimed perfectly.

Intensity Modulated Radiation Therapy (IMRT)

This is considered superior to 3D-CRT in the sense that it takes some of the guesswork out of treatments.

System algorithms determine how the beams should be placed, and calculate the radiation dosage to achieve optimal results. This technique also decreases unnecessary radiation exposure, so it can reduce toxicity related to radiation.

Stereotactic Body Radiotherapy (SBRT)

Stereotactic body radiotherapy (SBRT) is a technique in which a high dose of radiation is delivered to a relatively small area of cancer tissue to spare healthy tissue.

In contrast to other types of radiation therapy for lung cancer, SBRT sometimes offers a good chance for long-term survival or, possibly, a cure. SBRT may also be used, at times, for lung cancer that has spread. When only a few metastases from lung cancer are present, such as in the brain or liver, SBRT has, on occasion, resulted in long-term control of the disease.

This type of radiation is sometimes referred to by the name of the company that makes the machine being used. Some names you may hear in reference to SBRT include X-Knife, CyberKnife, Clinac, and Gamma Knife.

Internal Radiation

Internal radiation involves placement of a radioactive implant in your body, near the tumor. Also known as brachytherapy, a thin tube called a bronchoscope is used to place the implant into the precise area needed. The tube is removed after treatment, but the implant may be temporary or permanent.

For SBRT to be effective, tumors need to be small—usually less than 5 centimeters (about 2 inches) in diameter. The cancer being targeted should not be too close to the airways, heart, or other critical structures.

Brachytherapy is often used for palliative care, providing an efficient way to manage breathing difficulties that can occur as lung cancer progresses. It can substantially improve the quality of life, but it is not intended to cure cancer or prolong survival.

During Treatment

The radiation dosage, the duration of exposure, and the treatment process all depend on the type of radiation you are prescribed.

How External Therapy Is Administered

With external radiation, each treatment lasts for 15 to 30 minutes, usually administered daily over the course of several weeks.

Before your treatment, you may be given one or more skin tattoos, which are permanent ink marks about the size of a freckle overlying the tumor in your lung. This marks precisely where the radiation should be directed, although new techniques — such as Surface Guided Radiation Therapy (SGRT) — may offer greater precision and reduce the need for permanent skin markings.

The radiation oncologist makes adjustments to get the beam perfectly positioned, often as you lie still on a treatment table. They will then calculate a dose of radiation (measured in Gy, pronounced gray) that will be delivered over the duration of your therapy.

How Internal Therapy Is Administered

For internal therapy, you usually need to be admitted to the hospital for your implant placement. This requires a brief operation with general or local anesthesia. Your healthcare provider will use a tube and an imaging tool (X-ray or CT scan) to place the implant near your tumor.

How long the implant stays inside your body varies, depending on the dose being administered:

  • High-dose brachytherapy: With high-dose therapy, the implant may be left in for several minutes at a time while a large dose of radiation is emitted. Treatments may be repeated twice a day over a few days or once a day over the course of a few weeks. The application tube may be left in place until the series of radiation treatments are complete.Low-dose brachytherapy: With low-dose brachytherapy, an implant may be left in for one or more days to allow it to give off low doses of radiation the entire time. Some smaller implants are never removed, but will stop emitting radiation after several weeks.

Side Effects

There are both minor and severe side effects of radiation therapy that you should discuss with your healthcare provider before you begin treatments.

Managing Radioactivity

With a radioactive implant, your body may emit a small amount of radiation for a short time.

Early Side Effects 

These problems tend to occur shortly after starting radiation. They are usually mild and should not last long:

  • Fatigue (feeling tired)Skin changes

Hair loss usually occurs at the site of radiation: You may lose hair on your head when radiation is directed to your brain, or you may lose chest hair when radiation is directed to your lungs. Hair can grow back but it may grow back differently than before, and sometimes hair loss can be permanent.

Late Side Effects 

Side effects that can occur months or years after radiation treatment include:

  • Radiation-induced lung damage
  • Radiation pneumonitis (inflammation of the lungs)
  • Pulmonary fibrosis (can result from pneumonitis if not diagnosed and treated promptly)

Complications may affect any tissue area that was exposed to radiation. The higher the dose of radiation, the higher the risk of delayed side effects.

Survival rates for lung cancer are improving, which is a wonderful thing. But a longer life also means that there’s a higher chance of developing long-term side effects of radiation therapy.

A Word From Verywell

Radiation therapy can take a while to begin working, but the benefits continue for a long time after your treatment is completed. When you meet with your radiation oncologist, you will have follow-up tests and examinations to check on your progress.

Keep in mind that battling lung cancer is a long-distance run that may include lifelong monitoring, some setbacks, and, hopefully, many victories. As treatments continue to improve, you should be able to take advantage of more opportunities to enjoy a high quality of life as you continue your journey.