Respiratory/Lung Cancers

Lung Cancer

Background

Lung cancer is the leading cause of cancer deaths in the United States for both men and women. Lung cancer claims more lives each year than colon, prostate, ovarian, lymph and breast cancers combined.

People who smoke have the greatest risk of lung cancer. This also includes those exposed to second-hand smoke. Approximately two out of every three lung cancers are diagnosed in people over age 65, and most are older than 45. The average age at diagnosis is 71.

There are two main categories of lung cancer: small cell lung cancers and non-small cell lung cancers. They are distinguished by the appearance of cancer cells under a microscope.

Non-small cell lung cancers

Non-small cell lung cancers account for nearly 80 percent of lung cancers and spread more slowly in the body. There are three types of non-small cell lung cancers:

  • Adenocarcinoma is generally found in the mucus-producing glands of the lung. When it develops in the tiny lung sacs (alveoli), it is also called bronchioalveolar adenocarcinoma.
  • Squamous cell carcinoma typically originates in the lung's large breathing tubes (bronchi) and is closely linked to cigarette smoking.
  • Large cell carcinoma usually begins in the branches of the smaller breathing tubes (bronchioles).

Small cell lung cancers

Small cell lung cancers account for approximately 20 percent of lung cancers. They typically begin in the lung's bronchi and spread quickly, often to other parts of the body. Small cell lung cancer is also called oat cell cancer because of its oat-like appearance when viewed under a microscope.

Symptoms

Symptoms of lung cancer can include:

  • Coughing, either a new and persistent cough, or a change in the nature of a chronic "smoker's" cough
  • Coughing up blood, even in small amounts
  • Chest pain
  • Shortness of breath
  • Wheezing
  • Recurring pneumonia
  • Losing weight (non-intentional)

Risk Factors

Factors associated with an increased risk of developing lung cancer include:

  • Smoking remains the greatest risk factor for lung cancer. The risk of lung cancer increases with the number of cigarettes smoked each day and the number of years smoked. Quitting at any age can significantly lower the risk of developing lung cancer.
  • Exposure to second-hand smoke.
  • Exposure to radon gas. Radon is produced by the natural breakdown of uranium in soil, rock and water that eventually becomes part of the air you breathe. It is a colorless, odorless gas that can accumulate to unsafe levels in buildings and homes. Radon testing can be performed in high-risk areas to determine whether levels are safe.
  • Exposure to asbestos and other chemicals. Exposure to asbestos and other chemicals, such as arsenic, chromium, nickel, and tar can increase the risk of developing lung cancer, especially in someone who is a smoker.
  • Family history of lung cancer. There is an increased risk of lung cancer in people who have a family history of lung cancer in a first-degree relative (parent, sibling, child).
  • Excessive alcohol use. Moderate to heavy alcohol use may increase the risk of lung cancer.

Staging

Staging of non-small cell lung cancer

Stage I: Stage I is divided into Stages IA and IB:

    • The tumor is larger than 3 centimeters.
    • Cancer has spread to the main bronchus of the lung, and is at least 2 centimeters from the carina, where the trachea joins the bronchi.
    • Cancer has spread to the innermost layer of the membrane that covers the lungs.
    • The tumor partly blocks the bronchus or bronchioles and part of the lung has collapsed or developed pneumonitis, an inflammation of the lung.
  • Stage IA: The tumor is in the lung only and is 3 centimeters or smaller.

    Stage IB: One or more of the following is true:

Stage II Stage II is divided into Stages IIA and IIB:

    • The tumor is larger than 3 centimeters.
    • Cancer has spread to the main bronchus of the lung and is 2 centimeters or more from the carina, where the trachea joins the bronchi.
    • Cancer has spread to the innermost layer of the membrane that covers the lungs.
    • The tumor partly blocks the bronchus or bronchioles and part of the lung has collapsed or developed pneumonitis, an inflammation of the lung.
    • Or cancer has not spread to lymph nodes and one or more of the following is true:
    • The tumor may be any size and cancer has spread to the chest wall, or the diaphragm, or the pleura between the lungs, or membranes surrounding the heart.
    • Cancer has spread to the main bronchus of the lung and is no more than 2 centimeters from the carina, where the trachea meets the bronchi, but has not spread to the trachea.
    • Cancer blocks the bronchus or bronchioles and the whole lung has collapsed or developed pneumonitis, an inflammation of the lung.
  • Stage IIA: The tumor is 3 centimeters or smaller and cancer has spread to nearby lymph nodes on the same side of the chest as the tumor.

    Stage IIB: Cancer has spread to nearby lymph nodes on the same side of the chest as the tumor and one or more of the following is true:

Stage III: Stage III is divided into Stages IIIA and IIIB.

    • The tumor may be any size.
    • Cancer may have spread to the main bronchus, the chest wall, the diaphragm, the pleura around the lungs, or the membrane around the heart, but has not spread to the trachea.
    • Part or the entire lung may have collapsed or developed pneumonitis, an inflammation of the lung.
    • Heart
    • Major blood vessels that lead to or away from the heart
    • Chest wall
    • Diaphragm
    • Trachea
    • Esophagus
    • Sternum (chest bone) or backbone
    • More than one place in the same lobe of the lung
    • The fluid of the pleural cavity surrounding the lung
  • Stage IIIA: Cancer has spread to the lymph nodes on the same side of the chest as the tumor, and:

    Stage IIIB: The tumor may be any size and has spread to lymph nodes above the collarbone or the opposite side of the chest from the tumor; and/or to any of the following:

Stage IV: Cancer may have spread to lymph nodes and has spread to another lobe of the lungs or to other parts of the body, such as the brain, liver, adrenal glands, kidneys, or bone.

Staging of small cell lung cancer
Staging of small cell lung cancer is categorized according to extent of disease: limited-stage small cell lung cancer or extensive-stage small cell lung cancer.

Limited-stage small cell lung cancer: Cancer is found in one lung, the tissues between the lungs, and nearby lymph nodes only.

Extensive-stage small cell lung cancer: Cancer has spread outside of the lung where it began (such as both lungs) or to other parts of the body.

Treatment

Treatment of Stage I non-small cell lung cancer may include:

  • Early-stage lung cancer is often treated with the surgical removal of part of or the entire affected lung.
  • External radiation therapy for patients who cannot have surgery or choose not to have surgery.
  • Clinical trial of photodynamic therapy, electrocautery, cryosurgery, or laser surgery using an endoscope.

Treatment of Stage II non-small cell lung cancer may include:

  • Surgery, or surgery followed by chemotherapy.
  • External radiation therapy for patients who cannot have surgery or choose not to have surgery.
  • A clinical trial of radiation therapy following surgery.

Treatment of Stage IIIA non-small cell lung cancer that can be removed with surgery may include:

  • Surgery followed by chemotherapy.
  • A clinical trial of new combinations of treatments.

Treatment of Stage IIIA non-small cell lung cancer that cannot be removed with surgery may include:

  • Chemotherapy combined with radiation therapy.
  • External radiation therapy alone (for patients who cannot be treated with combined therapy).

Treatment of Pancoast tumors
Non-small cell lung cancer of the superior sulcus, often called Pancoast tumor, begins in the upper part of the lung and spreads to nearby tissues, such as the ribs and vertebrae. Treatment of Pancoast tumors may include:

  • Surgery
  • Radiation therapy
  • Surgery and radiation therapy
  • Chemotherapy combined with radiation therapy and surgery
  • A clinical trial of new combinations of treatments

Treatment of chest wall tumors
Some Stage IIIA non-small cell lung tumors that have grown into the chest wall may be completely removed. Treatment of chest wall tumors may include:

  • Surgery
  • Radiation
  • Surgery and radiation therapy
  • Chemotherapy combined with radiation therapy and/or surgery

Treatment of Stage IIIB non-small cell lung cancer may include:

  • Chemotherapy combined with external radiation therapy
  • External radiation therapy as palliative therapy, to relieve pain and other symptoms and improve the quality of life.
  • Clinical trials of new combinations of treatments.

Treatment of stage IV non-small cell lung cancer may include:

  • External radiation therapy as palliative therapy, to relieve pain and other symptoms and improve quality of life
  • Combination chemotherapy
  • Combination chemotherapy and targeted therapy
  • Laser therapy and/or internal radiation therapy using an endoscope
  • A clinical trial of new combinations of treatments

Treatment of limited-stage small cell lung cancer may include:

  • Combination chemotherapy and radiation therapy to the chest. Radiation therapy to the brain may later be given to patients with complete responses.
  • Combination chemotherapy without radiation to the chest for patients with lung problems or multiple medical problems. Radiation therapy to the brain may later be given to patients with complete responses.
  • Surgery followed by chemotherapy or chemotherapy plus radiation therapy to the chest. Radiation therapy to the brain may later be given to patients with complete responses.

Treatment of extensive-stage small cell lung cancer may include:

  • Combination chemotherapy; radiation therapy to the brain may later be given to patients with complete responses.
  • Radiation therapy to the brain, spine, bone, or other parts of the body where the cancer has spread, as palliative therapy to relieve symptoms and improve quality of life.
  • Clinical trials of new chemotherapy treatments.

References
National Cancer Institute, Mayo Clinic, Cancer Treatment Centers of America.