Lung cancer is the nation's third most common major cancer, after breast cancer in women and prostate cancer in men. Though lung cancer remains challenging to treat, doctors and researchers are making steady advances in finding it earlier. Some important things to know:

• Lung cancer has two main types: non-small cell and small cell.
• Most lung cancers are non-small cell, which has more treatment options.
• Smoking remains the leading cause of lung cancer.

Lung Anatomy

What is lung cancer?

Lung cancer occurs when abnormal cells develop in one or both lungs and then grow so quickly that the body's immune system cannot keep up. The abnormal cells can form tumors that keep your lungs from working. Left untreated, the cancer can spread to nearby lymph nodes and other parts of your body.

Who gets lung cancer?

About 235,000 new cases of lung cancer are diagnosed in the U.S. every year, according to the National Cancer Institute, and there are about 611,000 people in the U.S. living with it. 

Risk factors

Smoking: Smoking accounts for as much as 90% of lung cancers. It brings substances into the body that damage cells lining the lungs. Stopping smoking can significantly reduce the risk of many cancers and other diseases. Still, nearly 60% of lung cancers are diagnosed in people who have quit.

Secondhand smoke: Exposure to secondhand smoke causes thousands of lung cancer cases in the U.S. each year.

Age: In the U.S., more than two-thirds of patients are 65 or older when diagnosed.

Environment: Exposure to pollutants such as fuel exhaust and chemical vapors can increase risk. Exposure to radon gas, which can build up in homes and other buildings from the natural breakdown of uranium in soil, also increases risk.

Family history: Inherited genes can increase risk among smokers and nonsmokers. If you have a family history of lung cancer or worry that you’re at high risk, we offer expert genetic counseling and risk assessment to help you learn about and manage your risk.

Lung cancer survival rates

A key concept in understanding survival is five-year relative survival rate. This is the percentage of people who are alive five years after they were first diagnosed, compared to the general population. (It doesn’t count death from other causes.)

Lung cancer remains difficult to treat, especially because many patients are diagnosed in later stages. This means that overall survival rates remain discouraging. It’s important to know, though, that survival rates are only averages and can’t predict the outcome for any one patient.

Signs of hope: Survival rates have risen substantially over the past decade. Patients whose cancer is caught at the earliest stage have a survival rate of more than 90%. Researchers at the Knight Cancer Institute are working on new ways to treat lung cancer. Depending on your condition, you may qualify for one of our clinical trials.

Quality of life: While lung cancer sometimes cannot be cured, treatment can keep you comfortable and give you time to do things you want to do. You might set goals such as taking a special trip. Maybe you hope to see a child or a grandchild marry or graduate.

At the Knight Cancer Institute, your goals become our goals. We are devoted to extending and improving your life regardless of your long-term outlook.

Lung cancer types

Lung cancer has two main types, each with several subtypes.

Non-small cell lung cancer: This covers several types in which cancer cells form in lung tissue. Each is named for the type of cell it develops in. This group of lung cancers makes up about 85% to 90% of cases.

• Squamous cell carcinoma: This type begins in squamous cells. These thin, flat cells form the surface of the skin, the lining of hollow organs and the lining of respiratory and digestive tracts. Also called epidermoid carcinoma, this cancer most often develops in smokers.
• Large cell carcinoma: This cancer may begin anywhere in lung tissue. It tends to grow more rapidly than other non-small cell cancers.
• Adenocarcinoma: This slow-growing cancer type usually appears in the areas around the lungs. It occurs most often in smokers but is the most common type of lung cancer in nonsmokers.
• Other: Less common types include pleomorphic, carcinoid tumor, salivary gland carcinoma and unclassified carcinoma.

Small cell lung cancer: This aggressive cancer forms in lung tissue and can spread to other parts of the body. It occurs almost exclusively in heavy smokers and represents about 10%  to 15% of lung cancers. Subtypes include small cell carcinoma, also called oat cell cancer, and combined small cell carcinoma.

Symptoms of lung cancer

Lung cancer typically doesn't cause symptoms in early stages, and some symptoms can be caused by other conditions. Lung cancer is sometimes discovered after a chest X-ray for another condition. Talk with your doctor if you're concerned about:

• Chest discomfort or pain
• Bone pain
• A cough that doesn't go away or worsens
• Shortness of breath
• Wheezing
• Blood coughed up from the lungs
• Hoarseness
• Loss of appetite
• Weight loss for no known reason
• Severe fatigue
• Headaches
• Trouble swallowing
• Swelling in the face and/or neck veins

Lung cancer staging

Staging helps doctors see whether and how far lung cancer has spread. This helps guide treatment options. Your care team will determine the stage of your cancer based on:

• The size of the main tumor and whether it has grown into nearby areas
• Whether the cancer has spread to lymph nodes
• Whether the cancer has spread to other organs or body parts

Lung cancer information

• Lung Cancer, National Cancer Institute
• Lung Cancer, American Cancer Society
• American Lung Association 
• LUNGevity
• GO2 for Lung Cancer
• Lung Cancer Action Network
• Lung Cancer Research Foundation
• Secondhand Smoke and Cancer, National Cancer Institute

Stopping smoking

• OHSU help to quit smoking
• Oregon Tobacco Quit Line, Oregon Health Authority
• Tobacco: Health Benefits of Smoking Cessation, World Health Organization