Lung cancer is the leading cause of cancer death and the second most common cancer among both men and women in the U.S. It also has one of the lowest five-year survival rates of all cancer types.
One reason why lung cancer is so deadly is that it is hard to find in its early stages. It may take years for the lung cancer to grow and there usually are no symptoms early on. By the time you start to notice symptoms, the cancer often has spread to other parts of the body.
When a person has lung cancer, they have abnormal cells that cluster together to form a tumor. Unlike normal cells, cancer cells grow out of control, destroying the healthy tissue. These types of tumors are called malignant tumors. When the cancer cells grow too fast, they prevent organs of the body from functioning properly.
There are two main types of lung cancer: small cell lung cancer and non-small cell lung cancer. A third less common type of lung cancer is called carcinoid.
Small cell lung cancer (SCLC)
Small cell lung cancer is almost always associated with cigarette smoking and is usually treated with chemotherapy.
Non-small cell lung cancer (NSCLC)
Non-small cell lung cancer makes up about 80 percent of lung cancer cases. This type of cancer usually grows and spreads to other parts of the body more slowly than small cell lung cancer does. There are three different types NSCLC:
Adenocarcinoma: Often found in the outer area of the lung. It develops in the cells of epithelial tissues, which line the cavities and surfaces of the body and form glands.
Squamous cell carcinoma: Usually found in the center of the lung next to an air tube.
Large cell carcinoma: Can occur in any part of the lung and tends to grow and spread faster than the other cancers.
Lung carcinoid tumors are uncommon and tend to grow slower than other types of lung cancers. Carcinoids are very rare, slow-growing and most commonly treated with surgery.
Lung Cancer Symptoms
Many people with lung cancer don’t have symptoms until the disease is in its later stages. Because there are very few nerve endings in the lungs, a tumor could grow without causing pain or discomfort. When symptoms are present, they are different in each person, but may include:
- A cough that doesn’t go away and gets worse over time
- A chronic cough or “smoker’s cough”
- Constant chest pain
- Shortness of breath or wheezing
- Frequent lung infections such as bronchitis or pneumonia
- Coughing up blood
Some symptoms of lung cancer may not seem related to the lungs or breathing. These symptoms still be a sign of lung cancer because lung cancer usually does not cause symptoms in its earlier stages. This means some symptoms do not appear until the cancer has spread to other parts of the body. Some of these symptoms may include:
- Weight loss
- Loss of appetite
- Bone pain or fractures
- Blood clots
See your doctor right away if you notice any of these symptoms
What Causes Lung Cancer
Anyone can get lung cancer. Lung cancer occurs when cells in the lung mutate or change. Various factors can cause this mutation to happen. Most often, this change in lung cells happens when people breathe in dangerous, toxic substances. Even if you were exposed to these substances many years ago, you are still at risk for lung cancer.
Smoking causes about 90 percent of lung cancer cases. Tobacco smoke contains many chemicals that are known to cause lung cancer. If you still smoke, quitting smoking is the single best thing you can do for your lung health.
Smokers are not the only ones affected by cigarette smoke. If you are a former smoker, your risk is decreased, but has not gone away completely—you can still get lung cancer. Nonsmokers also can be affected by smoking. Breathing in secondhand smoke puts you are risk for lung cancer or other illnesses.
Radon exposure is the second-leading cause of lung cancer. Radon is a colorless, odorless radioactive gas that exists naturally in soil. It comes up through the soil and enters buildings through small gaps and cracks. One out of every 15 homes in the U.S. is subject to radon exposure. Exposure to radon combined with cigarette smoking seriously increases your lung cancer risk.
Exposure to certain hazardous chemicals poses a lung cancer risk. Working with materials such as asbestos, uranium, arsenic, cadmium, chromium, nickel and some petroleum products is especially dangerous. If you think you may be breathing in hazardous chemicals at your job, talk to your employer and your doctor to find out to protect yourself.
Genetic factors also may play a role in one’s chances of developing lung cancer. A family history of lung cancer may mean you are at a higher risk of getting the disease. If others in your family have or ever had lung cancer, it’s important to mention this to your doctor.
How Lung Cancer Is Diagnosed
Diagnosing lung cancer is different for each person. Your medical team chooses tests based on a number of factors, including your medical history, symptoms and a physical exam. Options may include diagnostic imaging such as X-rays, MRI and CT Scans or tissue sample biopsy.
How Lung Cancer Is Treated
The treatment for lung cancer depends on your lung cancer type, lung cancer stage and lung cancer treatment goals. Options may include surgery, radiation, chemotherapy, targeted therapy, immunotherapy, clinical trials and/or palliative care.
Sources: American Cancer Society, Centers for Disease Control and Prevention, American Lung Association and Mayo Clinic.
American Lung Association Lung Cancer Fact Sheet
American Lung Association