Also see Conditions We Treat, Lung Cancer.

When is radiation therapy recommended for lung cancer?

Radiation therapy delivers high-energy x-rays that can destroy rapidly dividing cancer cells. It has many uses in lung cancer:

• As primary treatment

• Before surgery to shrink the tumor

• After surgery to eliminate any cancer cells that remain in the treated area

• To treat lung cancer that has spread to the brain or other areas of the body

What are the most common types of lung cancer?

There are two major types of lung cancer. Non-small cell lung cancer (NSCLC) is the most common, accounting for 75 to 80% of those seen in the United States. Small cell lung cancer (SCLC) is less common, tends to grow more rapidly, and has a greater likelihood to have spread at diagnosis. SCLC is considered to be either limited (confined to the chest) or extensive stage (beyond the chest) at diagnosis.

For limited stage SCLC, radiation is targeted to the lung cancer and given concurrently with chemotherapy. For extensive stage SCLC, radiation therapy may be given to the lung for palliation of pain, shortness of breath, or hemoptysis (coughing up blood).

If initial treatment for SCLC results in a good response, radiation therapy may be directed to the brain to prevent the development of brain metastases as well.

For early stage NSCLC (Stage I and II) radiation alone may be used for patients who are unable to tolerate or who are not interested in surgery. Radiation therapy is also sometimes recommended in patients with early stage NSCLC who have undergone surgery to remove the tumor. When radiation is used after surgery, it is called "adjuvant" radiation therapy. Adjuvant RT decreases the chance that a tumor will return or recur following surgery, and is usually used if small amounts of tumor are thought to remain in the surgical bed, or for those patients who have lymph node involvement. For patients with known mediastinal involvement (N2 or N3 disease) who are considered unresectable (Stage IIIA or Stage IIIB) at diagnosis, chemotherapy and radiation are recommended to be used together. Using these two treatments concurrently may lead to a “synergistic” or “one plus one equals three” effect on the tumor.

What are the common side effects of radiation therapy to the lung?

The most common side effects of radiation therapy for lung cancer are:

• esophagitis (difficulty swallowing due to inflammation of the esophagus, the muscular tube between the mouth and stomach)

• pneumonitis (inflammation of the normal lung surrounding the tumor).

Both of these conditions are usually self-limited and improve after treatment is completed. Other side effects that may occur include fatigue, cough, and mild to moderate redness of the skin in the treatment area (similar to sunburn). Tell your radiation oncologist or nurse about any discomfort you may feel.

What kind of radiation do you give to treat lung cancer?

There are two main methods by which the radiation therapy treatments can be given: External beam radiation or Brachytherapy.

External beam radiation therapy involves a series of painless, daily (Monday through Friday) outpatient treatments delivered over several weeks. It works by focusing a beam of ionizing radiation to the tumor while sparing the surrounding tissue. The two main techniques for delivering external beam radiation therapy are: a) 3-dimensional conformal therapy (3-D conformal) which refers to a method of treatment delivery that incorporates 3-dimensional computer planning and treatment systems to produce a high-dose area of radiation that conforms to the shape of the area to be treated. This technique allows the delivery of precise doses of radiation to the targeted area through multiple treatment fields while sparing surrounding tissues, and b) Intensity modulated radiation therapy (IMRT) which utilizes a more sophisticated system of shields within the machine allowing a higher dose of radiation to be delivered to the tumor from multiple angles while minimizing effects on surrounding tissue. This form of 3-D conformal radiotherapy allows a precise adjustment of radiation beams to the tissue within the target area. It continues to be studied for lung cancer especially in our clinics where respiratory gating (synchronizing the delivery of radiation to the individual's own breathing cycle) is possible.

Brachytherapy may be recommended for specialized circumstances: This is a form of internal radiation therapy that may be helpful in addressing the part of the tumor filling your airway (endobronchial component) and obstructing your breathing. High-dose-rate brachytherapy (HDR) is used in our FROG Centers: During this procedure a bronchoscopy is performed placing one or two thin plastic tubes or catheters into the airways leading to the lungs. These tubes are connected to a special machine. A small amount of radioactive material passes through these catheters allowing a high dose of radiation to be delivered to a small, precise area while sparing surrounding normal tissue. The radiation procedure itself only takes about 10 minutes. The catheters are then removed at the end of each treatment before you leave the clinic.

When is radiation to the brain also given for lung cancer?

Radiation directed to the whole brain to prevent brain metastasis is typically given for patients with SCLC whose disease has responded to initial therapy. The brain is a common site of tumor spread (termed metastasis) in people with SCLC. Having radiation treatment of the brain after chemotherapy and before evidence of metastases develops, substantially reduces the chances of ever developing brain metastases and prolongs survival. This type of radiation therapy is called prophylactic cranial irradiation, or PCI. PCI has been so successful in SCLC patients that research trials are now underway to see if similar benefits can be seen in patients with NSCLC, too.

In patients who have spread of lung cancer to the brain at diagnosis or down the road, radiation therapy to the brain is often recommended to control symptoms and shrink those tumor deposits. Standard radiation machines can bathe the whole brain with radiation treatment, and some of our special machines (Gamma Knife, Cyberknife, etc.) can give highly focused doses to critical spots in the brain as well.

Why is PET/CT useful in the diagnosis and treatment of lung cancer?

PET/CT scanning improves the detection rate of malignancy compared to conventional diagnostic studies such as CT or radionuclide bone scans. This enhanced detection accuracy frequently alters diagnostic management and treatment decisions. Better targeting of the tumor can significantly impact on radiotherapy treatment planning volumes, and can help us avoid treating normal tissues unnecessarily.

What is respiratory gating?

Several of our clinics are incorporating breakthrough technologies of PET/CT, respiratory gating, and IMRT to treat lung cancer.

When you breathe, internal organs move by as much as several centimeters. As the lungs expand and contract while inhaling and exhaling, lung tumors move and even change shape, making precise targeting of radiation beams difficult. Respiratory gating is the process of turning the radiation beam on and off based on your breathing cycle. High doses of radiation ensure the best outcomes (greater control, tumor reduction, and potential cure), but higher radiation doses can only be delivered if the dose to normal tissues can be kept to safe levels. When the radiation beam is activated in synchronization with a patient's respiratory pattern, it targets the tumor only when it is in the optimal position and prevents the radiation beam from treating healthy tissues.

Our group was one of the first in the country to use respiratory-gated PET/CT fusion for planning, and respiratory-gated compensator based intensity modulated radiation therapy for individuals with lung cancer.

Also see Conditions We Treat, Lung Cancer.