Non-Small Cell Lung Cancer

By far the most common type of lung cancer, this accounts for more than 80 percent of all lung cancer cases. It usually grows slowly and often has few symptoms until it’s far advanced.  

Subtypes of Non-Small Cell Lung Cancer

  • Squamous Cell – Almost a third of non-small cell lung cancers are this subtype that often begin in the flat cells that line the inside of the airways in the lungs. They tend to be found in the central part of the lungs where the trachea (windpipe) joins the primary  bronchi (the main airway branches).
  • Adenocarcinoma – This type, accounting for about 40 percent of lung cancers, is usually found in the outer parts of the lung. It tends to grow more slowly than other types of lung cancer, is more common in women than in men and is more likely to occur in younger people. While it occurs most commonly in smokers or ex-smokers, it is the most common lung cancer seen in non-smokers.
  • Large cell (undifferentiated) carcinoma – Only a little over 10 percent of lung cancers are this type that can appear in any part of the lungs. Unlike the other types of Non-Small Cell Lung Cancer, undifferentiated carcinomas tend to grow and spread quickly.

Risk Factors for Non-Small Cell Lung Cancer

  • Genetics – People with immediate family members (parents, brothers, sisters) who have had cancer may be more likely to get the disease.
  • Tobacco – Smoking (cigarettes, cigars and pipes) is recognized as the leading cause of Non-Small Cell Lung Cancer. Both second-hand smoke (being exposed regularly to someone else who smokes) and the use of smoke-free tobacco products increase the risk of developing lung cancer.
  • Exposure to asbestos or other pollutants in the air – Exposure to asbestos in the workplace can increase Non-Small Cell Lung Cancer risks, especially for miners and workers in mills, shipyards and construction.
  • Industrial exposure – Breathing chemicals or minerals such as arsenic, chromium, nickel, soot or tar and/or other workplace chemicals over time may increase lung cancer risk.
  • Radon – A colorless, odorless radioactive gas prevalent in certain areas of the country where uranium exists in the soil or rocks, radon poses a serious risk and is the leading cause of lung cancer among non-smokers.
  • Prior cancer treatment – People who have had radiation therapy to the chest are at higher risk for lung cancer, particularly if they smoke.

Symptoms of Non-Small Cell Lung Cancer

Non-Small Cell Lung Cancers often grow slowly for a long time before symptoms develop, but tumors may grow large enough to interfere with air passageways.

Common symptoms that eventually develop include: 

  • A persistent cough, especially without a known cause, that does not go away, becomes chronic, or gets worse and causes pain.
  • Coughing up blood or rust-colored spit or phlegm.
  • Shortness of breath, painful breathing, or noisy breathing (called stridor).
  • Chest pain, especially pain that is often worse with deep breathing, coughing, or laughing.
  • Feeling fatigued, tired or weak; needing to nap frequently or for extended periods.
  • Frequent upper respiratory infections such as bronchitis and pneumonia that don’t go away or keep coming back.
  • Hoarseness, a chronic raspy or ragged quality to speech, or new onset of wheezing.
  • Bone pain

Stages of Non-Small Cell Lung Cancer

Stages are the levels of cancer development. Non-Small Cell Lung Cancer staging uses the TNM system of factors:

  • Tumor (T) describes the size of the original tumor.
  • Lymph Node (N) indicates whether the cancer has spread to the lymph nodes.
  • Metastasis (M) refers to whether cancer has spread to other parts of the body.

A number or the letter X is assigned to each factor with higher numbers indicating increasing severity. The letter X means information could not be assessed.

Stages are assigned once the TNM scores have been set:

  • Occult stage – Cancer cells are found in sputum, but not in the lung with imaging or bronchoscopy.
  • Stage 0 – The cancer is tiny, has not spread and is known as carcinoma in situ.
  • Stage I – Cancer may be present in underlying lung tissue, but lymph nodes are unaffected.
  • Stage II – Cancer has spread to nearby lymph nodes or into the chest wall.
  • Stage III – The cancer has spread from the lungs and the lymph nodes to nearby structures and organs, such as the heart, trachea and esophagus.
  • Stage IV – Cancer has metastasized throughout the body and may now affect the liver, bones or brain. 

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