Radiation therapy is a type of cancer treatment that uses high energy rays to destroy cancer cells and shrink tumors. Doctors may recommend it as either a stand-alone treatment or in combination with surgery, chemotherapy, or both.

This article describes what radiation therapy is, the different types of radiation therapy, and what a person can expect from this treatment.

It also looks at the risks and effectiveness of radiation therapy for lung cancer and lists some of the support services available for people living with lung cancer.

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Cells are the basic units of living things. They grow and divide to form new cells and eventually become damaged and die.

Unlike normal cells, cancer cells grow and divide rapidly and uncontrollably. In the case of lung cancer, this process may result in a solid tumor in the lungs.

Radiation therapy is a type of cancer treatment that uses high energy particles, or rays, to damage and destroy cancer cells. It works by creating small tears in the DNA inside cancer cells, which prevents the cells from growing and dividing, and causes them to die.

Radiation therapy also has the same effect on other rapidly dividing noncancerous cells. However, most of these healthy cells eventually recover once a person has completed their therapy.

Radiation therapy is typically a local treatment, meaning it does not have systemic, or widespread, effects on the body. As such, it aims to damage mainly cancerous cells while sparing as many healthy cells as possible.

Doctors may recommend radiation therapy for the following:

  • as a stand-alone treatment for lung cancer or in combination with surgery, chemotherapy, or both
  • to treat lung cancer that has spread to other parts of the body, such as the brain or bones
  • before surgery to shrink the lung tumor so it is easier to operate on and remove
  • after surgery to rid the body of any cancer cells surgeons may have been unable to remove
  • to relieve symptoms of lung cancer, such as:

There are different types of radiation therapy. The type a person receives depends on various factors, such as the:

  • type of lung cancer the person has
  • location and size of the tumor
  • person’s overall health

According to the National Cancer Institute, the two main types of radiation therapy for lung cancer are external beam radiation therapy (EBRT) and internal radiation therapy (IRT), also known as brachytherapy.

External beam radiation therapy

In EBRT, doctors focus radiation from outside the body onto the cancer cells inside the body. The process of EBRT is similar to receiving an X-ray, but the radiation dose is stronger.

The length of EBRT treatment can vary, but a person usually receives treatment 5 days a week for 5–7 weeks.

Doctors may use one of several techniques to administer EBRT. These include:

  • Three-dimensional conformal radiation therapy (3D-CRT): This technique uses special computers to map the precise location of the tumor and then target radiation beams at it from multiple directions. This helps reduce the risk of damage to healthy tissues.
  • Intensity-modulated radiation therapy (IMRT): This technique is similar to 3D-CRT. However, IMRT also allows doctors to adjust the strength of the radiation beams to limit damage to nearby healthy cells. Doctors typically use this technique when tumors are close to important structures, such as the spinal cord.
  • Stereotactic body radiation therapy (SBRT): Rather than administering small doses of radiation every day over a period of weeks, SBRT involves administering a higher dose of radiation in just one to five sessions. This technique involves placing a person in a special body frame to help prevent the movement of the lung tumor during breathing. Doctors may recommend SBRT for early stage lung cancers when surgery is not an option.


Internal radiation therapy (IRT), or brachytherapy, typically involves placing small radioactive pellets inside the cancerous tumor. Doctors may place the pellets during a procedure called a bronchoscopy or during open surgery.

A doctor may use brachytherapy to shrink small tumors in the airways. They may do this to alleviate a person’s symptoms or to shrink a tumor before surgery so it is easier to operate on and remove.

With brachytherapy, the radiation travels only a short distance from its source, limiting damage to nearby healthy tissues.

Typically, doctors remove the radioactive pellets after a short time. However, doctors sometimes leave them in place permanently, and the radiation weakens over the following weeks.

Below is some information on what to expect before, during, and after radiation therapy.

Before radiation therapy

Before receiving radiation therapy, a person will meet with a radiation oncologist and radiation therapist to discuss their treatment.

People receiving EBRT undergo a procedure called a simulation. During a simulation, the radiation oncologist and radiation therapist place small marks on the skin to define the treatment area for future radiation treatments.

These marks may be temporary ink marks or permanent tattoos. They help guide the radiation beams toward the cancer.

In some cases, radiation technicians may create a mold of the person’s body to help the person maintain the correct position during radiation therapy.

During radiation therapy

The exact procedure for radiation therapy depends on whether a person is receiving EBRT or brachytherapy.


During EBRT, a radiation technician uses a person’s skin markers to correctly position their body on the treatment table. At this time, a person may see colored lights directed at the marks. These help with accurate positioning.

The radiation technician then leaves the room but will be able to see the person through a window or on a television screen. The technician is able to communicate with them via a speaker.

During therapy, the person receiving the treatment must lie still but can breathe normally. They may hear noises from the machine but will not experience any sensations from the radiation.


A person who is about to undergo brachytherapy receives either a local or general anesthetic, so they will not feel any pain during the procedure.

The surgeon then uses a catheter to insert the radioactive material into the body. They typically use some type of imaging scan to guide them to the exact location of the tumor, such as:

The surgeon may remove the radioactive material within minutes or days of inserting it, or they may leave it in place permanently. In the case of permanent implants, the radioactivity fades away to nothing over time.

After radiation therapy

Radiation therapy is an effective treatment for most lung cancers. However, sometimes lung cancers can come back after successful treatment.

Once radiation therapy is complete, a person requires regular follow-up appointments to check for signs of cancer. In many cases, this type of aftercare will be lifelong.

Some potential signs of lung cancer recurrence include:

The above symptoms are not always signs of a cancer recurrence. However, anyone who experiences any of these symptoms after radiation therapy or any other type of cancer treatment should contact their doctor immediately to make a follow-up appointment.

Some people do not experience side effects from radiation therapy. However, some people may experience what medical professionals describe as “early” or “late” side effects.

Early side effects

Early side effects resolve within a few weeks of completing treatment. Some common examples include:

  • Fatigue: Tiredness and fatigue from radiation therapy may not improve with rest. A person may require time off work or school while they recover.
  • Hair loss: People may experience hair loss at the site of the radiation treatment, but the hair should eventually grow back once the healthy cells have had a chance to recover from the damage. In the meantime, a person can continue to protect the area from the sun.
  • Skin changes: People may experience peeling or blistering of the skin at the site of the radiation treatment. The following steps can help avoid further irritating the skin as it heals:
    • not wearing tight or irritating clothing
    • using mild, fragrance-free cleansing products
    • washing only in lukewarm water
    • not scrubbing or rubbing the skin when washing or drying
    • keeping the area protected from the sun

Late side effects

Late side effects may not develop until months or years after completing radiation therapy. They can occur in any part of the body that receives radiation.

People who receive higher doses of radiation have an increased risk of developing late side effects. People can discuss their individual risks with their oncologist before starting radiation therapy.

According to the American Cancer Society (ACS), radiation therapy can be an effective treatment for the two primary types of lung cancer: non-small cell lung cancers (NSCLCs) and small cell lung cancers (SCLCs).

The ACS notes that NSCLCs are less aggressive than SCLCs and are also more common: Whereas NSCLCs account for around 80–85% of lung cancers, SCLCs comprise around 10–15% of lung cancers.

According to a 2022 review, stereotactic body radiation therapy (SBRT) for early stage NSCLC successfully controlled the growth of the primary tumor in 85–95% of cases. In addition, between 55 and 91% of people who received SBRT for early stage NSCLC survived at least 3 years from the time of their initial diagnosis.

The effectiveness of radiation therapy for SCLC is less clear, although the ACS notes that this type of cancer tends to respond well to radiation therapy and chemotherapy. However, the ACS adds that SCLCs typically return at some point.

Below are some support services for people living with lung cancer.

American Cancer Society 24/7 Cancer Helpline

The American Cancer Society 24/7 Cancer Helpline is a service that provides support for people living with cancer. It connects them with cancer information specialists.


  • Phone: 800-227-2345

American Lung Association

The American Lung Association support network offers the following for lung cancer survivors and people living with lung cancer:

  • a helpline
  • a mentoring program
  • an online support group
  • in-person support groups



LUNGevity provides resources, support, and information for lung cancer survivors and people living with lung cancer.


Below are some answers to frequently asked questions about radiation therapy for lung cancer.

Does radiation work for lung cancer?

In many cases, radiation therapy is an effective treatment for lung cancer. A person may also require chemotherapy, surgery, or both as part of their overall treatment plan.

How many sessions of radiation are needed for lung cancer?

According to the ACS, external beam radiation therapy for NSCLC, the most common type of lung cancer, typically involves five sessions per week for 5–7 weeks.

However, the intensity of radiation treatments and the number of sessions a person requires depends on several factors, including:

  • the type and intensity of radiation therapy the person is receiving
  • whether the person is receiving any other cancer treatments, such as surgery or chemotherapy
  • the type of lung cancer the person has
  • whether the lung cancer has spread and if so, to what extent

Radiation therapy uses high energy rays to damage and destroy cancer cells. It is a common and oftentimes effective treatment for lung cancers. Doctors may use it instead of or in addition to other types of cancer treatment, such as surgery and chemotherapy.

There are two main types of radiation therapy for lung cancer: external beam radiation therapy (EBRT) and brachytherapy.

EBRT involves beaming radiation from outside the body onto the tumor. Brachytherapy involves placing radioactive material inside the tumor.

Some people may experience early side effects of radiation therapy within the weeks or months following treatment. Others may develop late side effects in the years following their treatment.

A person can discuss the potential side effects and risks of radiation therapy with their radiation oncologist.