Radiation Therapy for Lung Cancer: Success Rates - Verywell Health

Radiation therapy is a common treatment for lung cancer, but can it cure the disease? There's not a simple yes or no answer. The success rate of radiation depends on the type used, what it is being used for, the stage of the cancer, and much more.

In early-stage lung cancer, radiation may be tried as a curative approach, especially in people who are not expected to do well with surgery. While the term "cure" is rarely used, many people will remain cancer free.

With cancers that are large or have spread to nearby lymph nodes, radiation may be used to reduce the size of the tumor so that surgery can be done or to destroy any remaining cancer cells after surgery.

In advanced disease, radiation is most often used as a palliative treatment—a treatment designed to relieve symptoms and improve quality of life but not as a cure or to extend life.

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Lung Cancer Survival Rates

It's helpful to review the survival rates of the different types of lung cancer when looking at the potential benefits of radiation.

When reviewing these, however, it's important to note that no two lung cancers are alike. Even if two people develop cancers of the same type and same stage, they may have considerably different outcomes depending on many factors, such as the gene mutations present in the tumor.

In addition, there are limitations to using statistics, including that people aren't statistics. There is no "average" person who has an "average" journey with lung cancer.

Perhaps the most important limitation in discussing five-year survival rates with lung cancer is that treatments are improving and rapidly changing. The treatment you receive may not have existed five or 10 years ago, so the statistics may not be relevant to your case.

For example, for decades there was relatively little progress in lung cancer treatment. This began to change quickly, starting around the year 2010, first with targeted therapies and then immunotherapy. There was a new drug available every few months.

Even during the height of the COVID-19 pandemic, in May of 2020, six new medications or combinations of medications were approved to treat lung cancer. If you receive one of these treatments, statistics from 2010 to 2016 may mean little.

Non-small cell lung cancer is broken down into four stages, although three are important when discussing statistics, which are:

• Local disease: Near where the cancer started in the lungs
• Regional: Spread to nearby tissues or lymph nodes
• Distant: Spread (metastasized) to distant tissues or organs

The overall five-year survival rate for all stages is 25%. By the three groupings, five-year survival is:

• Local: 63%
• Regional: 35%
• Distant 7%

Small cell lung cancer is broken down into two primary stages—limited and extensive. Survival rates are also described based on whether the cancer is localized, has spread to nearby tissues, or is metastatic.

The overall five-year survival rate of all stages combined is 7%. By the three groupings, five-year survival is:

• Local: 27%
• Regional: 16%
• Distant: 3%

Small Cell Lung Cancer vs. Non-Small Cell Lung Cancer

There are many differences between small cell and non-small cell lung cancers.

Small cell cancers tend to grow near the large airways and cause symptoms soon after they are present. They tend to be aggressive and spread early (often to the brain).

Surgery is rarely an option, and the mainstay of treatment is radiation and chemotherapy in the early stages and chemotherapy plus immunotherapy in the later stages.

There are several types of non-small cell lung cancers, which are the type of lung cancer seen most often in women and people who have never smoked. They tend to grow in the outer regions of the lung and can become quite large before they are diagnosed.

The treatments vary significantly based on each stage and substage of the cancer. Fortunately, the development of targeted therapies and immunotherapy has changed the outlook for many of these cancers, even when diagnosed at stage 4, the most advanced stage, in which cancer has traveled to other parts of the body

Types of Radiation Therapy

To understand success rates when treating lung cancer with radiation therapy, it's important to look at the different methods/types of radiation and the goals of treatment. Radiation therapy has changed considerably in recent years and has become much more effective and precise (fewer side effects) than in the past.

Radiation therapy is a local therapy (like surgery) and generally treats cancer only where the radiation beams are aimed. It works by damaging the DNA within cancer cells.

Before radiation therapy is started, the area of the tumor to be treated is carefully mapped using what is known as four-dimensional computed tomography (4DCT).

External Beam Radiation Therapy

External beam radiation therapy is the type of radiation that many people are familiar with. With external beam radiation, high doses of radiation are delivered to a region of the body over a period of time. While there are variations, a typical example would be daily sessions five days per week for five weeks.

The area of a tumor is mapped using computed tomography (CT), magnetic resonance imaging (MRI), positron-emission tomography (PET), or PET-CT (integrating both PET and CT). The radiation is directed from outside of the body toward that region.

There are several different modifications of external beam radiation, including:

• Conventional (2D) radiation therapy is traditional radiation therapy and is not used often with lung cancer at this time.
• Conformal therapy (3D) radiation therapy is more specific in that it uses computers to direct radiation toward a tumor from three dimensions. This allows more precise delivery of higher-dose radiation to an area, with less damage to healthy tissue.
• Intensity modulated radiation therapy (IMRT) is similar to conformal therapy but is even more precise and, therefore, spares healthy tissue. The tumor is mapped from many angles to create a shape, and then higher doses of radiation are applied to the tumor, with lower doses going to nearby healthy tissue. This technique may be used when a tumor is near an important structure, such as the heart.

Examples of a few variations of the above may include:

• Volumetric modulated arc therapy (VMAT) is a type of IMRT that can be performed more rapidly.
• Image-guided radiation therapy, another type of IMRT, uses imaging to map the site and deliver the treatment precisely.
• Hypofractionated radiation therapy is an alternative to treat very small tumors. A higher dose of radiation is given with each treatment allowing for fewer treatments (and a shorter period to complete treatment).

Proton beam therapy is a type of radiation therapy that uses protons (one of the elementary particles in the atom) propelled at high speed by a cyclotron instead of photons (electromagnetic particles/waves) to damage tissue. It is used in similar situations as external beam radiation is and most often provides similar results.

The main advantage of proton therapy is when a tumor lies near a vital structure in the body as less tissue damage may occur. Traditional radiation travels through a tumor and reaches some tissue beyond the tumor before dying off. In contrast, proton therapy essentially "stops" and releases all the energy on the tumor without passing through to normal tissue.

While proton therapy may be given in somewhat higher doses (due to the lower risk of tissue damage), the outcomes of the two types of treatment are similar. In addition, proton therapy is only found in some regions of the United States, is usually very expensive, and is less likely to be covered by insurance.

External beam radiation (or proton beam therapy) may be given in a number of different situations, including:

• Before surgery (to reduce the size of a tumor/usually combined with chemotherapy)
• After surgery (to clean up any cancer cells that may remain after surgery/usually combined with chemotherapy)
• As a primary treatment (with or without chemotherapy) to slow the growth of a tumor
• To treat metastases
• To treat an area where cancer is growing (often at a distant site) in someone whose cancer is otherwise controlled on a treatment, such as targeted therapy
• For symptoms: Radiation therapy may be used to treat a number of symptoms, including pain or spinal cord compression due to bone metastases, bleeding, narrowing or obstruction of the airways, esophagus, or large vein in the neck (superior vena cava).
• For prevention: A type of external beam radiation called prophylactic cranial radiation is sometimes used for people with small cell lung cancer to prevent the spread of the cancer to the brain (brain metastases).
  

Brachytherapy (Internal Radiation Therapy)

Brachytherapy involves directly applying radiation (via pellets or seeds) to a tumor. It can be done during surgery or during a bronchoscopy. This is a procedure in which a tube with a camera is inserted through the nose or mouth and into the airways.

The radiation travels only a short distance from where the pellets are placed and may result in less damage to nearby healthy tissue than conventional radiation therapy.

Brachytherapy may be done as high-dose therapy, in which the pellets are placed for a short time (during the procedure) and then removed.

Or it may be done as low-dose therapy, in which the pellets emit a lower dose of radiation and are left in place for a few days. In some cases, the pellets may be left in place permanently, with the radiation decreasing over time.

Brachytherapy may be tried for a few different situations, including as a primary treatment for tumors that recur in or near the airways (and can be reached during a bronchoscopy).

Stereotactic Body Radiotherapy (SBRT)

Stereotactic body radiotherapy (SBRT) is also known as CyberKnife or gamma knife. Compared to conventional radiation therapy, SBRT uses a much higher dose of radiation directed at a very small area of tissue.

With SBRT, the intent is to stop a tumor from metastasizing, greatly reducing the chance that it will recur. To understand this goal, some people find it helpful to think of SBRT as doing surgery but with radiation instead.

There are two settings in which SBRT is most commonly used with lung cancer, which are:

• With early stage (stage 1), inoperable tumors (tumors that are less than 5 centimeters (cm) or roughly 2 inches in diameter
• With only a single or a few small metastases present in areas such as the brain, called oligometastatic disease.

There are a number of reasons why early-stage non-small cell lung cancer might be considered inoperable. Some of these are:

• When a tumor is located very near a vital structure and surgery could be dangerous
• In older people (though the definition of "older people" is relative)
• In people with other medical conditions that could make surgery riskier, such as lung diseases with poor lung function and unstable heart disease
• In people who simply don't want to undergo surgery

With early-stage lung cancers, there now studies looking at the benefits of SBRT compared to surgery, as well as some data on the benefits of treating oligometastatic disease.

Goals of Treatment With Radiation

If you are considering radiation therapy for lung cancer, it's very important to talk about the goals of treatment when discussing success rates and whether you should consider the treatment. Unfortunately, what patients expect isn't always what doctors hope to achieve.

In fact, in a study looking at people with advanced cancer, 69%–81% of people had different expectations (in this case, of chemotherapy) than did their doctors.

Goals with radiation may include:

• Extending life: For example, external radiation for more advanced lung cancers, treating isolated metastases in people who have tumors otherwise controlled on targeted therapies or immunotherapy, or preventive radiation in the brain to lower the chance of small cell lung cancers spreading
• Reducing the size of a tumor so that surgery might be done: For example, external beam radiation before lung cancer surgery (neoadjuvant therapy)
• Reducing the risk of recurrence after surgery: For example, when external beam radiation is given after surgery to clean up remaining cancer cells (adjuvant therapy)
  
• Cure: For example, SBRT with early-stage non-small cell lung cancers, or the combination of external beam radiation plus chemotherapy for limited stage lung cancers
• Symptom relief: Most often, external radiation therapy to some region (palliative treatment)

Knowing whether the goal of radiation therapy is to be cancer free or to extend life or to reduce symptoms is crucial.

Small Cell Lung Cancer (SCLC) Success Rate

Small cell lung cancer accounts for roughly 13% of lung cancers and tends to spread early (often to the brain) and aggressively. Roughly one-third of these cancers are diagnosed when they are considered "limited stage" tumors, and two-thirds are already extensive at the time of diagnosis.

With limited stage, there are different degrees of tumor involvement. Local tumors are confined to the site in the lung where the cancer began, but the term "very local" is sometimes used when considering what tumors may be treated with surgery (uncommon with small cell lung cancer).

The term "regional," in contrast, describes limited stage tumors that may have spread beyond the initial site of the tumor within the lungs. Extensive tumors are those that have spread to distant regions.

Radiation therapy (along with chemotherapy) is used most commonly with limited stage small cell lung cancer (local and regional disease) and less often with extensive stage disease.

Limited Stage

For people with limited stage small cell lung cancer, radiation therapy with a goal to cure the cancer (curative intent) has been shown to improve survival. It is considered the standard of care for those who can tolerate the combination of radiation and chemotherapy. With this care, up to a third of these cancers may be curable (or at least lead to long-term survival).

The American Society for Radiation Oncology guidelines recommend that radiation (which is usually given in combination with chemotherapy) be used as early as possible after diagnosing early-stage disease.

If lymph nodes are not involved (no evidence that the cancer has spread to lymph nodes), stereotactic body radiotherapy (SBRT), or external beam therapy, is strongly recommended. Chemotherapy should be given in addition to SBRT. External beam therapy is usually given once or twice a day for three to seven weeks.

Prophylactic cranial irradiation (PCI) is not recommended with very small local tumors but is strongly recommended for people with regional disease who have responded to radiation and chemotherapy.

It's difficult to cite the success rate of radiation therapy in many studies since it is usually given along with chemotherapy. Since radiation is given in combination with chemotherapy (called chemoradiation), it's difficult to separate the effect of radiation alone on treatment.

Despite being an early-stage cancer, limited small cell lung cancer treatment has advanced more slowly than that of non-small cell lung cancer. The overall five-year survival rate ranges from 30%–35% when the guidelines are followed.

While radiation therapy is a routine part of treatment for limited-stage cancer, a few analyses attempted to figure out the survival benefit of adding radiation therapy to the combined treatment.

The addition of radiation therapy to chemotherapy appears to have a 5.4% survival benefit at two to three years after treatment. It also appears to control local growth of tumor about 25% better than chemotherapy alone.

Starting radiation therapy early (within 30 days of chemotherapy) also translates to improved survival at two years out compared to beginning radiation therapy later in treatment.

Success Rates

Survival rates are estimates and may not account for recent treatment advances. People are not statistics.

Extensive Stage

Radiation isn't used as commonly to treat extensive stage small cell lung cancer, and the mainstay of treatment is chemotherapy and immunotherapy. Immunotherapy teaches the immune system to attack some types of lung cancer cells.

Traditionally, radiation in this setting is used primarily to treat the symptoms of metastatic lung cancer, such as headaches due to brain metastases and pain from bone metastases.

That said, a review of studies found that consolidation therapy (radiation to decrease the size of the tumor in the lungs) may be helpful for some people compared to standard treatment.

While the treatment didn't improve overall survival, people treated with consolidation therapy had improved progression free survival, meaning that it took longer for their tumors to grow and spread within the lungs.

The role of prophylactic cranial irradiation (to attempt to prevent brain metastases) is more controversial, especially given potential side effects with memory and concentration. Fortunately, studies are in progress to better define the role.

Non-Small Cell Lung Cancer (NSCLC) Success Rate

The effects of treatments for non-small cell lung cancer are reported in different ways. In some cases, these are divided by the four stages of the disease. In others, they are roughly broken down into three stages: local tumors (stage 1 and some stage 2 tumors), regional (some stage 2 and some stage 3 tumors), and distant (stage 4 lung cancer).

In other cases, a study may simply refer to "early-stage lung cancer," which sometimes includes stage 1, stage 2, and stage 3A. Other studies look at other differences, such as studying only people who had stage 1A NSCLC.

Stage 1 (and 2A) Non-Small Cell Lung Cancer (NSCLC)

Stage 1 non-small cell lung cancer is potentially curable in many people—even those who are older or have medical conditions that can make surgery undesirable.

Since stage 1 lung cancer has not spread beyond the tumor's original site or to lymph nodes, radiation is not usually used before or after surgery. Radiation may, however, be used as the primary treatment as an alternative to lung cancer surgery among people who have inoperable tumors and has now become the standard of care.

To illustrate this, the percentage of people who received radiation as a single initial treatment for stage 1 NSCLC increased from 14.7% in 2010 to 25.7% in 2016.

SBRT vs. Surgery: Stage 1A

A 2021 study compared the one-year and three-year survival rates of people with stage 1A NSCLC who received either stereotactic body radiotherapy (SBRT) or surgery. For both groups, the overall survival was 91% at one year.

At three years, the survival rate for those who had SBRT was 87%, and for those with surgery was 84%. The conclusion was that, with stage IA tumors, SBRT was "non-inferior" (not worse than surgery).

Another study found that SBRT was excellent for controlling the growth of early lung cancers. In this study, the estimated chance that growth of the original tumor at four years out was 96%.

Some people (and some tumors) are better candidates for SBRT as a treatment for early lung cancer. This includes people who have peripheral tumors (surgery is often preferred for tumors in the central areas of the lungs), tumors that are unlikely to have spread to lymph nodes, and tumors in much older people or those who have reduced lung or heart function.

SBRT vs. External Beam Radiation for Stage 1 Lung Cancer

SBRT has also been compared to conventional external beam radiation for stage 1 lung cancer. Compared with standard radiation, survival with SBRT is almost twice as high.

Looking at these studies and more, SBRT is now considered the standard of care for people who have peripheral cancers (cancers located in the outer parts of the lungs rather than centrally) who have stage 1 to stage 2A NSCLC considered inoperable or who do not wish to undergo surgery.

Stage 1 NSCLC

In select people, the benefit of SBRT for early stage non-small cell lung cancers (stage 1) may be similar to that of surgery.

Stage 2 Non-Small Cell Lung Cancer

The role of radiation in therapy in stage 2 non-small cell lung cancer can depend on whether a tumor is stage 2A or 2B but may include:

• Curative therapy as the primary treatment with SBRT (especially stage 2A tumors)
• For incomplete margins after surgery (if some of a tumor could not be removed, or if cancer cells were close to the edge in a sample removed with surgery)
• Adjuvant therapy, to address any cancer cells that may remain behind after surgery

As noted above, SBRT is now the standard of care for stage 2A tumors that are considered inoperable and in a reasonable location.

Stage 2 Non-Small Cell Lung Cancer

There are significant differences between Stage 3A non-small cell lung cancer and stage 3B non-small cell lung cancer, with traditional thought thinking of stage 1 to stage 3A tumors as potentially operable and stage 3B and stage 4 tumors inoperable, though that thought may be changing.

The treatment of stage 3 NSCLC is also expected to change significantly in the near future as treatments such as targeted therapies (that zero in on genetic mutations found in the tumor cells) and immunotherapy become used in the earlier stages of the disease; not just in stage 4 lung cancer.

For many people with stage 3 NSCLC, the combination of radiation (external beam radiation) and chemotherapy is standard of care, with adjuvant immunotherapy used for those who do not progress with the radiation and chemotherapy. With this combination, long-term survival is possible for some people.

Some people with stage 3 NSCLC (up to 60%), however, may be unable to tolerate curative doses of radiation therapy, such as those who have a low performance status (a measure of how well they can perform everyday activities, which may predict how well they can tolerate treatment).

When this is the case, radiation therapy or chemotherapy have traditionally been used one treatment at a time. This approach may be changing as studies now show a survival advantage to using the treatments together.

In addition, the use of either targeted therapies alone (when a treatable mutation is present) or immunotherapy in this setting is being evaluated. However, there are not yet large studies comparing the outcomes of the approaches.

Since targeted therapies have been known to result in extended or even long-term control for people even with stage 4 tumors, researchers are optimistic that recommendations will be changing.

Looking at success rates of radiation (combined with chemotherapy and/or immunotherapy) for people with stage 3 NSCLC, a 2018 study found that adding immunotherapy to radiation and chemotherapy extended life.

The overall survival rate at 24 months for those receiving radiation plus chemotherapy and immunotherapy was 66.3% compared to 55.6% for those only receiving radiation and chemotherapy.

The median time to death or distant metastases (spread to distant organs) was 28.3 months in the group receiving all three treatments compared to 16.2 months in those receiving radiation and chemotherapy alone.

As far as the best type of external beam radiation therapy for stage 3 NSCLC, a 2017 study compared people receiving intensity modulated radiation therapy (IMRT) to those receiving 3D conformal radiation therapy. The two-year overall survival was the same between the two groups, but those receiving IMRT had fewer side effects.

Surgery in Stage 3 and Stage 4 Non-Small Cell Lung Cancer

Treatment approaches are being examined with stage 3 (and stage 4) NSCLC. Though radiation and chemotherapy are considered standard of care, the role of surgery in these locally advanced or even metastatic lung cancers is again being considered.

A 2016 study actually found that surgery in people who were appropriate candidates may significantly improve survival for some people. This study looked at people with both stage 3 and stage 4 NSLC.

For people who did not have surgery, the median overall survival was 11.9 months in people who received both radiation and chemotherapy, 10.5 months for those who only received chemotherapy, and 3.7 months for those who received only radiation.

Most Lung Cancers are Treatable

A very concerning finding was noted in this study. A full 27% of people received no treatment. Unless a person is in very bad health or has very advanced disease, treatments are usually available that may extend life and reduce symptoms.

Stage 4 Non-Small Cell Lung Cancer

Radiation therapy is used less often with stage 4 non-small cell lung cancer, but there are a few settings where it can be helpful, including:

• Palliation: The use of external beam therapy can greatly reduce pain from bone metastases and may also help with symptoms such as a cough, shortness of breath, coughing up blood due to a tumor.
• Oligometastatic disease: Stereotactic body radiotherapy (SBRT) has been increasingly used to treat isolated or just a few metastases, especially when a primary tumor is well controlled on a targeted therapy or immunotherapy.

Oligometastatic Disease

The treatment of metastases has been confusing to some who think of radiation as a local treatment alone. This may include a few "spots" on the brain or other regions. It is usually used when a person has a tumor that is basically stable on one of the targeted therapies or immunotherapy but develops metastases despite these.

Doctors use the term "rogue tumors" to describe some of these metastases that develop while the primary cancer is not growing. When used in the appropriate setting, SBRT for oligometastatic disease may prolong both progression-free and overall survival.

Palliative Therapy

The definition of success with palliative therapy is difficult to quantify as it is used to control symptoms rather than extend life. Bone metastases are common with lung cancer and can be extremely painful. Radiation may be used along with other treatments but is the most effective method for reducing pain and rapid pain relief.

Influencing Factors

There are a number of factors that can influence the success rate of radiation therapy, and it's important to keep these in mind when looking at general statistics that compare people as a whole.

Stage

The difference between success rates (and types) of radiation can be summed up as the traditional difference between local and systemic (throughout the body) therapies.

Local therapies treat a tumor where it began and include surgery and radiation. Systemic therapies treat cancer cells wherever they may happen to be in the body and include treatments such as chemotherapy, targeted therapy, and immunotherapy.

The earlier the stage, the greater the likelihood that a curative radiation approach can be used, similar to that of surgery. In local stages, radiation may be used alone.

In regional stages, radiation may be used to reduce the size of a tumor for surgery or reduce the chance of a recurrence. In distant stages, the goals change to extending life and reducing symptoms.

Age

Sensitivity to radiation therapy, not surprisingly, can change with age, and that can have an impact both on its effectiveness in curing a cancer/reducing recurrence risk and in side effects of the treatment.

The many different ways that age may affect your radiation treatment are complex and can be confusing (some effects may balance out others). The important thing is to talk to your radiation oncologist about how your age might affect your treatment.

With lung cancer, one concern that is often raised is cognitive side effects (for example, memory loss) with whole-brain radiation to small cell lung cancer. To make the best decision for your care, it's important to be fully aware of your treatment's potential benefits and potential risks.

Sex

We are learning there are some small but significant differences in how people of different sexes respond to radiation therapy.

These are enough so that radiation oncologists are now talking about "gender-dependent radiation therapy." This means designing treatment based not only on tumors and physical characteristics (weight and height) but also on the sex of the patient.

Radiation works by causing breaks in DNA, and males and females may differ in how their bodies recognize and attempt to repair those breaks in DNA. Some of the factors that can affect this are the inflammatory response in the body and levels of estrogen (hormone with higher concentrations in women). Overall, females appear to be more sensitive to the effects of radiation.

Radiation therapy is more likely to be curative for females than males, but that comes with a drawback. Females are also more likely to have side effects. The differences are significant enough that it's likely that sex will also be considered in planning radiation treatments for lung cancer in the future.

Currently, radiation oncologists look at several factors such as height and weight in making their calculations, but it's likely that sex will also come into play in the future.

Treatment Responses

Radiation therapy is often combined with other treatments (such as surgery, chemotherapy, or radiation) for lung cancer, and the effectiveness of some of these combinations are discussed above.

The abscopal effect is a relatively new and exciting effect that is sometimes seen when radiation is combined with immunotherapy (checkpoint inhibitors). This effect occurs when radiation therapy to one region (say, the brain) results in the control of the growth of cancer in other areas (say, the lungs or the adrenal glands).

There are different theories on why the effect occurs, but it's thought that the death of cells from radiation trains immune cells that can then travel to other regions of the body to treat cancer cells. It can be thought of in much the same way as how a vaccine works to prevent an infection.

In one study, researchers found that people who had been treated with external beam radiation at any time survived significantly longer (twice as long) when later treated with a checkpoint inhibitor, in this case, Keytruda (pembrolizumab).

The effect has also been seen with SBRT. Checkpoint inhibitors can be very effective. They sometimes lead to a durable response, but only a minority of people respond to these drugs.

In a study in which SBRT was used to one site of metastasis at the same time as Keytruda was given, 41% of people responded to the combination, but only 19% to the Keytruda alone.

While uncommon, the abscopal effect is exciting when it occurs, and researchers are looking for factors that might increase the chance of seeing this response.

Smoking

Does current smoking affect lung cancer survival or the effects of radiation therapy?

Smoking, in general, is associated with poorer survival with lung cancer. A 2019 study found that, among current heavy smokers, men were 1.75 times more likely and women 2 times as likely to die from all causes.