Lung Cancer

The lungs are a pair of cone-shaped organs in the chest that bring oxygen into the body as you breathe in. They release carbon dioxide, a waste product of the body's cells, as you breathe out. Each lung has sections called lobes. The left lung has two lobes. The right lung is slightly larger and has three lobes. Two tubes called bronchi lead from the trachea (windpipe) to the right and left lungs. The bronchi are sometimes also involved in lung cancer. Tiny air sacs called alveoli and small tubes called bronchioles make up the inside of the lungs..

A thin membrane called the pleura covers the outside of each lung and lines the inside wall of the chest cavity. This creates a sac called the pleural cavity. The pleural cavity normally contains a small amount of fluid that helps the lungs move smoothly in the chest when you breathe.

There are two main types of lung cancer: non-small cell lung cancer and small cell lung cancer.

There are several types of non-small cell lung cancer.

Each type of non-small cell lung cancer has different kinds of cancer cells. The cancer cells of each type grow and spread in different ways. The types of non-small cell lung cancer are named for the kinds of cells found in the cancer and how the cells look under a microscope:

• Squamous cell carcinoma: Cancer that forms in the thin, flat cells lining the inside of the lungs. This is also called epidermoid carcinoma.
• Large cell carcinoma: Cancer that may begin in several types of large cells.
• Adenocarcinoma: Cancer that begins in the cells that line the alveoli and make substances such as mucus.

Other less common types of non-small cell lung cancer are: adenosquamous carcinoma, sarcomatoid carcinoma, salivary gland carcinoma, carcinoid tumor, and unclassified carcinoma.

Risk factors for non-small cell lung cancer.

Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk to your doctor if you think you may be at risk for lung cancer.

Risk factors for lung cancer include the following:

• Smoking cigarettes, pipes, or cigars, now or in the past. This is the most important risk factor for lung cancer. The earlier in life a person starts smoking, the more often a person smokes, and the more years a person smokes, the greater the risk of lung cancer.
• Being exposed to secondhand smoke.
• Being exposed to asbestos, arsenic, chromium, beryllium, nickel, soot, or tar in the workplace.
• Being exposed to radiation from any of the following:
  • Radiation therapy to the breast or chest.
  • Radon in the home or workplace.
  • Imaging tests such as CT scans.
  • Atomic bomb radiation.
• Living where there is air pollution.
• Having a family history of lung cancer.
• Being infected with the human immunodeficiency virus (HIV).
• Taking beta carotene supplements and being a heavy smoker.

Older age is the main risk factor for most cancers. The chance of getting cancer increases as you get older.

When smoking is combined with other risk factors, the risk of lung cancer is increased.

Signs of non-small cell lung cancer.

Sometimes lung cancer does not cause any signs or symptoms. It may be found during a chest x-ray done for another condition. Signs and symptoms may be caused by lung cancer or by other conditions. Check with your doctor if you have any of the following:

• Chest discomfort or pain.
• A cough that doesn’t go away or gets worse over time.
• Trouble breathing.
• Wheezing.
• Blood in sputum (mucus coughed up from the lungs).
• Hoarseness.
• Loss of appetite.
• Weight loss for no known reason.
• Feeling very tired.
• Trouble swallowing.
• Swelling in the face and/or veins in the neck.
• Tests that examine the lungs.

Tests and procedures to diagnose and stage non-small cell lung cancer are often done at the same time. In addition to asking about your personal and family health history and doing a physical exam, your doctor may perform the following tests and procedures:

• Laboratory tests: Medical procedures that test samples of tissue, blood, urine, or other substances in the body.
• Chest x-ray: An x-ray of the organs and bones inside the chest.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the chest, taken from different angles.
• Sputum cytology: A procedure in which a pathologist views a sample of sputum (mucus coughed up from the lungs) under a microscope, to check for cancer cells.
• Thoracentesis: The removal of fluid from the space between the lining of the chest and the lung, using a needle. A pathologist views the fluid under a microscope to look for cancer cells.

There are different types of treatment.

Different types of treatments are available for patients with non-small cell lung cancer. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

The following types of treatment are used:

Surgery

Four types of surgery are used to treat lung cancer:

• Wedge resection: Surgery to remove a tumor and some of the normal tissue around it. When a slightly larger amount of tissue is taken, it is called a segmental resection.
• Pneumonectomy: Surgery to remove one whole lung
• Lobectomy: Surgery to remove a whole lobe (section) of the lung.
• Sleeve resection: Surgery to remove part of the bronchus.

After the doctor removes all the cancer that can be seen at the time of the surgery, some patients may be given chemotherapy or radiation therapy after surgery to kill any cancer cells that are left. Treatment given after the surgery, to lower the risk that the cancer will come back, is called adjuvant therapy.

Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy:

• External radiation therapy uses a machine outside the body to send radiation toward the area of the body with cancer.
• Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer.

Stereotactic body radiation therapy is a type of external radiation therapy. Special equipment is used to place the patient in the same position for each radiation treatment. Once a day for several days, a radiation machine aims a larger than usual dose of radiation directly at the tumor. By having the patient in the same position for each treatment, there is less damage to nearby healthy tissue. This procedure is also called stereotactic external-beam radiation therapy and stereotaxic radiation therapy.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy).

Targeted therapy

Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells.

Immunotherapy

Immunotherapy is a treatment that uses the patient's immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defenses against cancer.

Immune checkpoint inhibitor therapy is a type of immunotherapy used to treat some patients with advanced non-small cell lung cancer.

Laser therapy

Laser therapy is a cancer treatment that uses a laser beam (a narrow beam of intense light) to kill cancer cells.

Electrocautery

Electrocautery is a treatment that uses a probe or needle heated by an electric current to destroy abnormal tissue. For tumors in the airways, electrocautery is done through an endoscope.

Radiosensitizers

Radiosensitizers are substances that make tumor cells easier to kill with radiation therapy. The combination of chemotherapy and radiation therapy given with a radiosensitizer is being studied in the treatment of non-small cell lung cancer.

For more information, visit Cancer.gov 

Source: PDQ® Adult Treatment Editorial Board. PDQ Breast Cancer Treatment. Bethesda, MD: National Cancer Institute. This information should not be used to make decisions about insurance reimbursement.