Lung cancer is a type of cancer that begins in the lungs. Your lungs are two spongy organs in your chest that take in oxygen when you inhale and release carbon dioxide when you exhale. Lung cancer is the leading cause of cancer deaths in the United States, among both men and women. Lung cancer claims more lives each year than colon, prostate, ovarian, lymph and breast cancers combined. People who smoke have the greatest risk of lung cancer. The risk of lung cancer increases with the length of time and number of cigarettes smoked. If you quit smoking, even after smoking for many years, you can significantly reduce your chances of developing lung cancer.

Complications of Lung Cancer

Lung cancer can cause complications, such as:

• Shortness of breath. People with lung cancer can experience shortness of breath if cancer grows to block the major airways. Lung cancer can also cause fluid to accumulate around the lungs, making it harder for the lungs to expand fully when you inhale.
• Coughing up blood. Lung cancer can cause bleeding in the airway, which can cause you to cough up blood (hemoptysis). Sometimes bleeding can become severe. Treatments are available to control bleeding.
• Pain. Advanced lung cancer that spreads to the lining of the lung or to another area of the body can cause pain. Tell your doctor if you experience pain. Pain may initially be mild and intermittent, but can become constant. Medications, radiation therapy and other treatments may help make you more comfortable.
• Fluid in the chest (pleural effusion). Lung cancer can cause fluid to accumulate in the space that surrounds the lungs in the chest cavity (pleural space). Pleural effusion can result from cancer spreading outside the lungs or in reaction to lung cancer inside the lungs. Fluid accumulating in the chest can cause shortness of breath. Treatments are available to drain the fluid from your chest and reduce the risk that pleural effusion will occur again.
• Cancer that spreads to other parts of the body (metastasis). Lung cancer often spreads (metastasizes) to other parts of the body — most commonly the opposite lung, brain, bones, liver and adrenal glands. Cancer that spreads can cause pain, nausea, headaches or other signs and symptoms depending on what organ is affected. In some cases, treatments are available for isolated metastasis, but in most cases, the goal of treatment for metastasis is only to relieve signs and symptoms.
• Death. Unfortunately, survival rates for people diagnosed with lung cancer are very low. In most cases, the disease is fatal. People diagnosed at the earliest stages have the greatest chances for a cure. Your doctor can discuss your chances for survival with you.

Causes of Lung Cancer

Smoking causes the majority of lung cancers — both in smokers and in people exposed to secondhand smoke. But lung cancer also occurs in people who never smoked and in those who never had prolonged exposure to secondhand smoke. In these cases, there may be no clear cause of lung cancer. Doctors have identified factors that may increase the risk.

How smoking causes lung cancer

Doctors believe smoking causes lung cancer by damaging the cells that line the lungs. When you inhale cigarette smoke, which is full of cancer-causing substances (carcinogens), changes in the lung tissue begin almost immediately. At first your body may be able to repair this damage. But with each repeated exposure, normal cells that line your lungs are increasingly damaged. Over time, the damage causes cells to act abnormally and eventually cancer may develop.

Signs & Symptoms of Lung Cancer

Lung cancer typically doesn't cause signs and symptoms in its earliest stages. Signs and symptoms of lung cancer typically occur only when the disease is advanced.

Signs and symptoms of lung cancer may include:

• A new cough that doesn't go away
• Changes in a chronic cough or "smoker's cough"
• Coughing up blood, even a small amount
• Shortness of breath
• Chest pain
• Wheezing
• Hoarseness
• Losing weight without trying
• Bone pain
• Headache

Diagnosis of Lung Cancer

Tests to diagnose lung cancer

If there's reason to think that you may have lung cancer, your doctor can order a number of tests to look for cancerous cells and to rule out other conditions. In order to diagnose lung cancer, your doctor may recommend:

• Imaging tests. An X-ray image of your lungs may reveal an abnormal mass or nodule. A CT scan can reveal small lesions in your lungs that might not be detected on an X-ray.
• Sputum cytology. If you have a cough and are producing sputum, looking at the sputum under the microscope can sometimes reveal the presence of lung cancer cells.
• Tissue samples (biopsy). A sample of abnormal cells may be removed in a procedure called a biopsy in order to diagnose lung cancer. Your doctor can perform a biopsy in a number of ways, including bronchoscopy, in which your doctor examines abnormal areas of your lungs using a lighted tube that's passed down your throat and into your lungs; mediastinoscopy, in which an incision is made at the base of your neck and surgical tools are inserted behind your breastbone to take tissue samples from lymph nodes; and needle biopsy, in which your doctor uses X-ray or CT images to guide a needle through your chest and into a suspicious lump or nodule to collect cells. A biopsy sample may also be taken from lymph nodes or other areas where cancer has spread, such as your liver.

Lung cancer staging

Once your lung cancer has been diagnosed, your doctor will work to determine the extent, or stage, of your cancer. Your cancer's stage helps you and your doctor decide what treatment is most appropriate.

Staging tests may include imaging procedures that allow your doctor to look for evidence that cancer has spread beyond your lungs. These tests include CT scans, magnetic resonance imaging (MRI), positron emission tomography (PET) and bone scans. Not every test is appropriate for every person, so talk with your doctor about which procedures are appropriate for you.

Stages of non-small cell lung cancer

• Stage I. Cancer at this stage has invaded the underlying lung tissue but hasn't spread to the lymph nodes.
• Stage II. This stage cancer has spread to neighboring lymph nodes or invaded the chest wall or other nearby structures.
• Stage IIIA. At this stage, cancer has spread from the lung to lymph nodes in the center of the chest.
• Stage IIIB. The cancer has spread locally to areas such as the heart, blood vessels, trachea and esophagus — all within the chest — or to lymph nodes in the area of the collarbone or to the tissue that surrounds the lungs within the rib cage (pleura).
• Stage IV. The cancer has spread to other parts of the body, such as the liver, bones or brain.

Stages of small cell lung cancer

• Limited. Cancer is confined to one lung and to its neighboring lymph nodes.
• Extensive. Cancer has spread beyond one lung and nearby lymph nodes, and may have invaded both lungs, more-remote lymph nodes, or other organs, such as the liver or brain.

Treatments of Lung Cancer

You and your doctor choose a cancer treatment regimen based on a number of factors, such as your overall health, the type and stage of your cancer, and your preferences. Options typically include one or more treatments, including surgery, chemotherapy, radiation therapy or targeted drug therapy. In some cases you may choose not to undergo treatment. For instance, you may feel that the side effects of treatment will outweigh the potential benefits. When that's the case, your doctor may suggest comfort care to treat only the symptoms the cancer is causing, such as pain.

Surgery

During surgery your surgeon works to remove the lung cancer and a margin of healthy tissue. Procedures to remove lung cancer include:

• Wedge resection to remove a small section of lung that contains the tumor along with a margin of healthy tissue
• Segmental resection to remove a larger portion of lung, but not an entire lobe
• Lobectomy to remove the entire lobe of one lung
• Pneumonectomy to remove an entire lung

If you undergo surgery, your surgeon may also remove lymph nodes from your chest in order to check them for signs of cancer.

Lung cancer surgery carries risks, including bleeding and infection. Expect to feel short of breath after lung surgery. Your lung tissue will expand over time and make it easier to breathe. Your doctor may recommend a respiratory therapist who can guide you through breathing exercises to aid in your recovery.

Chemotherapy

Chemotherapy uses drugs to kill cancer cells. One or more chemotherapy drugs may be administered through a vein in your arm (intravenously) or taken orally. A combination of drugs usually is given in a series of treatments over a period of weeks or months, with breaks in between so that your body can recover. Chemotherapy can be used as a first line treatment for lung cancer or as additional treatment after surgery. In some cases, chemotherapy can be used to lessen side effects of your cancer.

Radiation therapy

Radiation therapy uses high-powered energy beams, such as X-rays, to kill cancer cells. Radiation therapy can be directed at your lung cancer from outside your body (external beam radiation) or it can be put inside needles, seeds or catheters and placed inside your body near the cancer (brachytherapy). Radiation therapy can be used alone or with other lung cancer treatments. Sometimes it's administered at the same time as chemotherapy.

Targeted drug therapy

Targeted therapies are newer cancer treatments that work by targeting specific abnormalities in cancer cells. Targeted therapy options for treating lung cancer include:

• Bevacizumab (Avastin). Bevacizumab stops a tumor from creating a new blood supply. Blood vessels that connect to tumors can supply oxygen and nutrients to the tumor, allowing it to grow. Bevacizumab is usually used in combination with chemotherapy and is approved for advanced and recurrent non-small cell lung cancer. Bevacizumab carries a risk of bleeding, blood clots and high blood pressure.
• Erlotinib (Tarceva). Erlotinib blocks chemicals that signal the cancer cells to grow and divide. Erlotinib is approved for people with advanced and recurrent non-small cell lung cancer that haven't been helped by chemotherapy. Erlotinib side effects include a skin rash and diarrhea.

Clinical trials

Clinical trials are studies of experimental lung cancer treatment methods. You may be interested in enrolling in a clinical trial if lung cancer treatments aren't working or if your treatment options are limited. The treatments studied in a clinical trial may be the latest innovations, but they don't guarantee a cure. Carefully weigh your treatment options with your doctor. Your participation in a clinical trial may help doctors better understand how to treat lung cancer in the future.

Supportive care

When treatments offer little chance for a cure, your doctor may recommend you avoid harsh treatments and opt for supportive care instead. If you're receiving supportive care, your doctor may treat signs and symptoms to make you feel more comfortable, but you won't receive treatment aimed at stopping your cancer. Supportive care allows you to make the most of your final weeks or months without enduring treatment side effects that can negatively impact your quality of life.

Prevention of Lung Cancer

There's no sure way to prevent lung cancer, but you can reduce your risk if you:

• Don't smoke. If you've never smoked, don't start. Talk to your children about not smoking so that they can understand how to avoid this major risk factor for lung cancer. Many current smokers began smoking in their teens. Begin conversations about the dangers of smoking with your children early so that they know how to react to peer pressure.
• Stop smoking. Stop smoking now. Quitting reduces your risk of lung cancer, even if you've smoked for years. Talk to your doctor about strategies and stop-smoking aids that can help you quit. Options include nicotine replacement products, medications and support groups.
• Avoid secondhand smoke. If you live or work with a smoker, urge him or her to quit. At the very least, ask him or her to smoke outside. Avoid areas where people smoke, such as bars and restaurants, and seek out smoke-free options.
• Test your home for radon. Have the radon levels in your home checked, especially if you live in an area where radon is known to be a problem. High radon levels can be remedied to make your home safer. For information on radon testing, contact your local department of public health or a local chapter of the American Lung Association.
• Avoid carcinogens at work. Take precautions to protect yourself from exposure to toxic chemicals at work. In the United States, your employer must tell you if you're exposed to dangerous chemicals in your workplace. Follow your employer's precautions. For instance, if you're given a face mask for protection, always wear it. Ask your doctor what more you can do to protect yourself at work. Your risk of lung damage from these carcinogens increases if you smoke.
• Eat a diet full of fruits and vegetables. Choose a healthy diet with a variety of fruits and vegetables. Food sources of vitamins and nutrients are best. Avoid taking large doses of vitamins in pill form, as they may be harmful. For instance, researchers hoping to reduce the risk of lung cancer in heavy smokers gave them beta carotene supplements. Results showed the supplements actually increased the risk of cancer in smokers.
• Drink alcohol in moderation, if at all. Limit yourself to one drink a day if you're a woman or two drinks a day if you're a man. Anyone age 65 and older should drink no more than one drink a day.
• Exercise. Aim to achieve at least 30 minutes of exercise on most days of the week. Check with your doctor first if you aren't already exercising regularly. Start out slowly and continue adding more activity. Biking, swimming and walking are good choices. Add exercise throughout your day — park farther away from work and walk the rest of the way or take the stairs rather than the elevator.

When to seek Medical Advice

• Make an appointment with your doctor if you have any signs or symptoms that worry you.
• If you smoke and want to stop in order to reduce your risk of lung cancer, make an appointment with your doctor. Your doctor can recommend strategies for quitting, such as counseling, medications and nicotine replacement products.