Nonsmall cell lung cancer is more widespread than small cell lung cancer, and generally it grows and spreads more gradually. The remaining lung cancers are all non-small cell (NSCLC).
There are three sub-types of NSCLC. The cells in these sub-types fluctuate in size, shape, and chemical make-up.
Squamous cell carcinoma: About 25% – 30% of all lung cancers are Squamous cell carcinomas. They are linked with a history of smoking and tend to be found centrally, near a bronchus.
Squamous cell carcinoma generally starts in the bronchi and doesn’t usually spread as rapidly as do other lung cancers
Adenocarcinoma: This type of cancer accounts for about 40% of lung cancers and is typically found in the outer region of the lung. Adenocarcinoma is more commonly found in women than in men.
Large-cell undifferentiated carcinoma: This kind of cancer accounts for about 10% – 15% of reported lung cancers. It appears in any part of the lung and tends to grow and spread quickly throughout the body ensuing in a poor prediction of recovery.
Large cell carcinoma is any lung tumor that cannot be classified
As cigarette smoking is a major cause of lung cancer nowadays, it is important to appreciate how smoking affects and injures the lungs. This is because smoke inhalation damages the normal cleaning process by which the lung protects itself from injury.
The bronchi which conduct inhaled air to the lung tissues are lined with a single coating of cells on which lies a defensive coating of mucus. The hair-like cilia on these cells beat in a regular rhythm to advance mucus upwards continually from the lung removing any inhaled particles which may have become trapped in the process.
The competence of this cleaning mechanism is damaged very quickly by smoke inhalation. The cilia disappear and the coating they lie in thickens in an attempt to protect the fine underlying tissues from injury. Once this damage has occurred, the lung can no longer keep itself uncontaminated.
As a result, the cancer-producing agents in cigarette smoke remain ensnared in the mucus on the surface lining of the airway. They then pass into the cells before being removed by coughing which is the only cleansing mechanism remaining.
Once they are within the body, these chemicals, and their by-products, alter the very nature of the cells in the lungs slowly and increasingly until finally cancer develops.