Lung Cancer

Definition

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

• 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

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Causes

Cancer occurs when cells in the body divide without control or order. If cells keep dividing when new cells are not needed, a mass of tissue forms. This growth is called a tumor. Cancer growths can invade nearby tissue. It can then spread to other parts of the body. Regular damage increases the turnover of cells.

The following are known to damage to the lungs, and cause 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

Things that may increase your chances of lung cancer are:

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

Most professional groups suggest lung cancer screening with a low-dose CT scan for those at high risk. High risk includes being 50 to 80 years old, history of heavy smoking, and being a current smoker or quit within last 15 years.

Symptoms

Symptoms and signs 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
• Clubbing—tips of fingers and toes become wider and rounder

Diagnosis

The doctor will ask about symptoms and past health. A physical exam will be done. The doctor will also ask about:

• Smoking habits past or present
• Things you may have come in contact with that can harm lungs
• Family history of cancer

Tests may include:

• Sputum cytology—mucus from the lungs is sent to a lab
• Biopsy—a sample of lung tissue is removed and looked at under a microscope

Images of the lungs and chest may be taken with:

• Chest x-ray
• CT scan of chest
• PET scan
• PET/CT scan
• Bone scan

The doctor will use results from all tests to determine the stage of cancer. Staging is used to guide your treatment plan. Lung cancer is staged from 1 to 4. Stage 1 cancer is contained in a small area. Stage 4 caner is one that has spread to other parts of the body.

Lung cancer screening may help to find lung cancer at early stages in those at high risk.

Treatment

The goal of treatment is to remove as much cancer as possible and control the symptoms.

Surgery

Surgery is done to remove the tumor and nearby tissue. Lymph nodes may also need to be removed. The type of surgery depends on the stage and area. Common choices include:

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

Radiation Therapy

Radiation therapy may be part of treatment. Radiation can kill cancer cells and shrink tumors. The therapy may also be used to relieve symptoms such as shortness of breath. External radiation is usually used to treat lung cancer. 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 as pills, injections, or through 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 chemical is injected into the bloodstream. It lingers in cancer cells longer than normal ones. 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—medicine or substances target parts of the cancer cells.
• Immunotherapy—medicine or substances 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.

References

• Cancer immunotherapy. American Cancer Society website. Available at: https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/immunotherapy.html.
• General information about non-small cell lung cancer. National Cancer Institute website. Available at: https://www.cancer.gov/types/lung/patient/non-small-cell-lung-treatment-pdq.
• General information about small cell lung cancer. National Cancer Institute website. Available at: https://www.cancer.gov/types/lung/patient/small-cell-lung-treatment-pdq.
• Lung cancer. American Cancer Society website. Available at: https://www.cancer.org/cancer/lung-cancer.html.
• Non-small cell lung cancer. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/non-small-cell-lung-cancer.
• Small cell lung cancer. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/small-cell-lung-cancer.
• Targeted cancer therapies. National Cancer Institute website. Available at: https://www.cancer.gov/about-cancer/treatment/types/targeted-therapies/targeted-therapies-fact-sheet.
• What do I need to know about lung cancer screening? American Lung Association website. Available at: http://www.lung.org/lung-health-and-diseases/lung-disease-lookup/lung-cancer/learn-about-lung-cancer/lung-cancer-screening.