What Is Lung Cancer? How Many Stages Are There

Lung cancer is generally defined as a malignant tumor that grows in one or both lungs, typically forming in the airways and glands.

The development of lung cancer affects the body’s exchange of carbon dioxide for oxygen in the lungs, making breathing – as well as many everyday activities – difficult for a person who has been diagnosed with the disease.

Smoking is the leading risk factor for lung disease; a patient’s exposure to radon is the second. Additional risk factors include exposure to secondhand smoke, air pollution, asbestos, and arsenic. Genetic predisposition may also affect a patient’s likelihood of developing lung cancer.

Signs and symptoms of lung cancer are often mistaken for other diseases, which frequently worsen once the cancer has already spread to other organs. Early symptoms for lung cancer include:

  • Shortness of breath
  • Wheezing
  • Chest pains that worsen by breathing or coughing
  • Weight loss
  • Loss of appetite
  • Weakness and/or fatigue
  • Hoarseness
  • Persistent cough
  • Coughing up blood

More advanced symptoms for lung cancer include:

  • Headaches and dizziness
  • Bone pain
  • Jaundice

Because many signs and symptoms of lung cancer are often associated with other diseases, it is critical that a patient seek medical attention for treatment in the event he or she suspects that anything is wrong.

Once a patient is diagnosed with lung cancer, a pathologist assigns a lung cancer stage, or classification, that assists the oncologist in determining the most appropriate course of treatment based on the extent of the cancer’s progression.

Lung cancer staging, however, does not affect the patient’s overall prognosis.
Various blood tests and body scans are typically used in the staging of lung cancer.

Guidelines for the staging of lung cancer include the size and location of the tumor, the number of tumors present, and the appearance of cancer cells under a microscope. There are four general phases of lung cancer staging:

  • Stage I: the earliest stage of cancer, which has not spread to the lymph nodes
  • Stage II: cancerous cells have spread to the lymph nodes
  • Stage III: cancer has spread to lymph nodes outside of the lungs, often on the same side as the cancer’s origin
  • Stage IV: the most advanced lung cancer stage in which the tumor has spread to other parts of the lungs or distant organs in the body. The 5-year survival rate for patients diagnosed with stage 4 lung cancer is less than 1 percent. However, numerous factors indicate how long a patient may live with Stage 4 lung cancer, including the type of cancer, location, and the patient’s general health at the time of diagnosis.

Lung cancer can trigger paraneoplastic syndromes, disorders that are brought on when the body’s white blood cells destroy good cells in the nervous system. Symptoms for these disorders can include muscle tone loss, dizziness, slurred speech, seizures or vision difficulties, and may begin to occur even before a patient has been diagnosed with cancer.

Statistics from the American Cancer Society reveal that approximately 159,000 people in the United States die each year from lung cancer, making the disease the cause for more than 1/3 of all cancer-related deaths in the country.

Despite this alarming statistic, and despite a projected annual statistic of 219,000 new cases, research for lung cancer remains significantly underfunded in the United States.

Although new scientific developments that have occurred within the last five years have allowed scientists to understand more about the biology of lung cancer, much more progress must be made in the funding and development of research regarding this deadly disease.