Lung Cancer: Questions & Answers

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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 is often 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, chemotherapy may also be used. 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 about any discomfort you may feel.

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

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.

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.

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.