Lung Cancer

Definition

Lung cancer is a disease in which cancer cells grow in the lungs. The most common type of lung cancer include:

Non-small cell lung cancer—generally grows and spreads more slowly (most common) Small cell lung cancer—generally grows more quickly and is more likely to spread to other parts of the body

Lung cancer is the leading cause of cancer deaths in the US for both men and women.

Lung Cancer
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Causes

Cancer occurs when cells in the body 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 growths. These growths can invade nearby tissues. Cancer that has invaded nearby tissues can then spread to other parts of the body.

The following can cause damage to the cells in the lungs, leading to lung cancer:

First- or second-hand smoke from cigarettes, cigars, or pipes Exposure to asbestos (a type of mineral) or radon (radioactive gas)
Risk Factors

Factors that may increase your chances of lung cancer:

Smoking Using chewing tobacco Exposure to second-hand smoke Exposure to to asbestos or radon Having a lung disease, such as tuberculosis Family or personal history of lung cancer Exposure to to certain air pollutants Exposure to to coal dust Radiation therapy that was used to treat other cancers HIV infection
Symptoms

Symptoms may include:

A cough that does not 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
Diagnosis

The doctor will ask about your symptoms and medical history. A physical exam will be done. The doctor will also ask about:

Smoking history Substances that you have been exposed to Family history of cancer

Tests may include:

Sputum cytology—a test that examines of a sample of mucus from the lungs Biopsy—removal of a sample of lung tissue to be examined under a microscope

Imaging tests evaluate the lungs and other structures. These may include:

Chest x-ray Spiral CT PET scan PET/CT scan Bone scan

The physical exam combined with all of your test results, will help to determine the stage of cancer you have. Staging is used to guide your treatment plan. Like other cancers, lung cancer is staged from I-IV. Stage I is a very localized cancer, while stage IV indicates a spread to other parts of the body.

Treatment

The goal of treatment is to eliminate the cancer and/or control the symptoms.

Surgery

Surgery involves removing the tumor and nearby tissue. Lymph nodes may also need to be removed. The type of surgery depends on the location of the tumor such as:

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

Radiation therapy is the use of radiation to kill cancer cells and shrink tumors. This may also be used to relieve symptoms such as shortness of breath. External radiation is usually used to treat lung cancer. With this treatment, radiation is directed at the tumor from a source outside of the body.

Chemotherapy

Chemotherapy is the use of drugs to kill cancer cells. This may be given in many forms, including pill, injection, and via a catheter. Chemotherapy is often used to kill lung cancer cells that have spread to other parts of the body.

Newer Treatments

Researchers continue to study ways to treat lung cancer. The National Cancer Institute considers these potential therapies:

Photodynamic therapy (PDT)—A type of laser therapy. A chemical is injected into the bloodstream. It is then absorbed by the cells of the body. The chemical rapidly leaves normal cells. It will remain in cancer cells for a longer time. A laser aimed at the cancer activates the chemical. This chemical then kills the cancer cells that have absorbed it. This treatment may also be used to reduce symptoms. Cryosurgery—A treatment that freezes and destroys cancer tissue.

Other treatments that are being researched include:

Targeted therapy—involves using medications or substances to target certain molecules in the cancer cells Immunotherapy—involves using medications or substances made by the body to increase or restore the body's natural defenses against cancer
Prevention

To help reduce your chances of lung cancer:

Do not start smoking. If you smoke, talk to your doctor about how to successfully 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. Try to avoid or limit occupational exposures.

The American Lung Association and American Cancer Society both suggest that screening for lung cancer with a low-dose CT scan may be considered if you are a smoker (or former smoker), aged 55-74 years, and have a history of heavy smoking (such as one pack a day for 30 years).

EBSCO Medical Review Board Mohei Abouzied, MD, FACP 201709 20130930