Understanding Lung Cancer

Normal cells grow, divide and die as the human body needs them. Lung cancer develops when cells in the lungs begin to grow out of control. Cancer cells act differently from normal cells because of damage or a change in the cells’ DNA, the genes that tell cells what to do. Cancer cells grow at an accelerated rate but do not die. Instead, they continue to grow and form a group of abnormal cells called a tumor.


There are a variety of reasons a person may develop lung cancer, but some causes are more prevalent than others. Smoking is the leading cause of lung cancer and is responsible for 87% of lung cancer cases. Exposure to secondhand smoke is estimated to cause an additional 3,000 lung cancer cases each year. Exposure to radon, a naturally occurring, odorless, colorless gas in some homes causes an estimated 20,000 lung cancer deaths each year.

There can be several symptoms of lung cancer including:

  • A cough that won’t go away
  • Coughing up blood
  • Chest, back or shoulder pain
  • Shortness of breath
  • Wheezing
  • Hoarseness
  • Being tired
  • Weight loss

If you or someone you know has symptoms or may be at risk for lung cancer, talk with your health care provider about your concerns and to determine whether you are a good candidate for lung cancer screening.

How do I protect myself from getting lung cancer?

Quit or do not ever start using tobacco
If you smoke or use tobacco in any form, quit. As soon as you quit, your body begins to repair the damage done by smoking.

Avoid secondhand smoke
Make your home and car smoke-free. Encourage family, friends and co-workers to quit smoking.

Test your home for radon
Simple, inexpensive test kits are available at most home improvement stores.

I've been diagnosed with lung cancer. What happens now?

After the type and stage of lung cancer is identified, you and your family can discuss treatment options with your team of health care professionals. Treatment plans are based on the type and stage of lung cancer and the patient’s overall health.

Many people benefit from a combination of treatments including:

  • Surgery to remove the tumor
  • Chemotherapy (medication that kills or shrinks the tumor)
  • Radiation therapy (X-rays that damage cancer cells)

Your team of health care professionals will be able to answer any questions you have. To learn more about what questions you should ask, read our “What to Ask Your Doctor” resource.


Researchers are continually exploring new treatment options for those people diagnosed with lung cancer. Before treatments are made available to the public, testing takes place to ensure treatments are safe and effective and to identify which treatment options work best. If a treatment seems promising after years of study in a lab, it is tested in people in studies called “clinical trials.” If the treatment being tested is ultimately shown to be safe and effective, it may be approved to be made available to the public.

For researchers, clinical trials are a crucial step in evaluating the efficacy of a new treatment. For participants, a clinical trial may provide access to experimental therapies or treatment options for their condition.

It is important to speak to your health care provider about new research and treatment options that may be available for you. Because they involve treatments not yet approved to the public, clinical trials are very strictly regulated by the U.S. Food and Drug Administration, and can only be participated in on a voluntary basis. For each trial, researchers use eligibility standards to choose the right participants. Not everyone who wants to join is eligible.

You can learn more about current research from patient advocacy groups like Respiratory Health Association, pharmaceutical companies, and academic research institutions. RHA offers links to local clinical trials in lung cancer and other lung diseases as a resource for people seeking information about these opportunities.


For more information, visit the Lung Cancer section of our Library.