Definition

Lung cancer is a disease in which cancer cells grow in the lungs.

Cancer occurs when cells in the body (in this case lung cells) divide without control or order. Normally, cells divide in a regulated manner. If cells keep dividing uncontrollably when new cells are not needed, a mass of tissue forms, called a growth or tumor. The term cancer refers to malignant tumors, which can invade nearby tissue and can spread to other parts of the body. A benign tumor does not invade or spread.

Lung cancers are divided into two types:

Non-small Cell Lung Cancer—generally grows and spreads more slowly (This is the more common type of lung cancer.)

Small Cell Lung Cancer—generally grows more quickly and is more likely to spread to other parts of the body

	Lung Cancer
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Causes

The following can cause damage to the cells in the lungs that can lead to lung cancer:

• First- or second-hand cigarette, cigar, or pipe smoke
• Asbestos (a group of minerals that occur naturally as fibers and are used in certain industries)
• Radon (an invisible, odorless, and tasteless radioactive gas in soil and rocks)

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. Risk factors for lung cancer include:

• Cigarette smoking
• Cigar and pipe smoking
• Exposure to second-hand smoke, also called environmental tobacco smoke (the smoke in the air when someone else smokes)
• Exposure to radon
• Exposure to asbestos
• Lung diseases, such as tuberculosis (TB)
• Personal history of lung cancer
• Exposure to certain air pollutants, such as by-products of the combustion of diesel and other fossil fuels, are linked to lung cancer, although the relationship is not yet clear.
• Coal dust

Symptoms

Symptoms include:

• A cough that doesn't go away and worsens over time
• Constant chest pain
• Coughing up blood
• Shortness of breath, wheezing, or hoarseness
• Repeated problems with pneumonia or bronchitis
• Swelling of the neck and face
• Loss of appetite or weight loss
• Fatigue

Note: These symptoms may also be caused by other, less serious health conditions. Anyone experiencing these symptoms should see a doctor.

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. The doctor will also ask about the following:

• Smoking history
• Exposure to environmental and occupational substances
• Family history of cancer

Tests may include:

• Chest x-ray
• Sputum cytology—examination of a sample of mucus from the lungs
• Spiral CT—a special type of x-ray of the lungs
• Biopsy—removal of a sample of lung tissue to be tested for cancer cells. Methods of lung biopsy include:
  • Bronchoscopy—a thin, lighted tube inserted into the mouth or nose and through the windpipe to look into the breathing passages. Through this tube, the doctor can collect cells or small samples of tissue.
  • Needle aspiration—a needle inserted through the chest into the tumor to remove a sample of tissue
  • Thoracentesis—use of a needle to remove a sample of the fluid around the lungs to check for cancer cells
  • Thoracotomy—surgery to open the chest and examine lung tissue

Treatment

Once lung cancer is found, staging tests are performed to find out if the cancer has spread and, if so, to what extent.

Surgery

Surgery will require removal of the cancerous tumor and nearby tissue, and possibly nearby lymph nodes. The type of surgery depends on the location of the tumor in the lung. Surgeries include:

• Segmental or wedge resection—removal of only a small part of the lung
• Lobectomy—removal of an entire lobe of the lung
• Pneumonectomy—removal of an entire lung

Radiation Therapy or Radiotherapy

This is the use of radiation to kill cancer cells and shrink tumors. Radiation therapy may also be used to relieve symptoms such as shortness of breath. Radiation may be:

• External radiation therapy—directed at the tumor from a source outside the body (more common for treating lung cancer)
• Internal radiation therapy—radioactive materials placed into the body in or near the cancer cells

Chemotherapy

This is the use of drugs to kill cancer cells. Chemotherapy may be given in many forms including: pill, injection, and via a catheter. The drugs enter the bloodstream and travel through the body killing mostly cancer cells, but also some healthy cells. Chemotherapy is often used to kill lung cancer cells that have spread to other parts of the body.

Promising New Treatments

The use of photodynamic therapy (PDT) and cryosurgery is not widespread or well-established. The National Cancer Institute considers both treatments potential therapies.

• Photodynamic therapy (PDT)—a type of laser therapy where a chemical is injected into the bloodstream and absorbed by the cells of the body. The chemical rapidly leaves normal cells but remains in cancer cells for a longer time. A laser aimed at the cancer activates the chemical, which then kills the cancer cells that have absorbed it. This treatment may also be used to reduce symptoms of lung cancer when the cancer cannot be removed through surgery.
• Cryosurgery—a treatment that freezes and destroys cancer tissue

Prevention

To reduce your risk of getting lung cancer:

• Don't start smoking.
• If you smoke, quit.
• Avoid places where people are smoking.
• Test your home for radon gases and asbestos. Have these substances removed if they are in the home.
• Do not work or live in a place with asbestos.

RESOURCES:

American Cancer Society
http://www.cancer.org

American Lung Association
http://www.lungusa.org

CANADIAN RESOURCES:

Canadian Cancer Society
http://www.cancer.ca

The Canadian Lung Association
http://www.lung.ca

References:

American Cancer Society website. Available at: http://www.cancer.org.

National Cancer Institute website. Available at: http://www.cancer.gov/.

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