Most Common Type of Lung Cancer

To describe the most common type of lung cancer it's helpful to first describe the different forms of the disease since the answer can vary depending on smoking status and gender.

There are two major types of lung cancer. Non-small cell lung cancer is the most common type of lung cancer overall accounting for roughly 80 percent of lung cancers. Small cell lung cancers are responsible for around 15 percent of lung cancers in the United States. 

Non-small cell lung cancers are in turn broken down into 3 types.

• Lung Adenocarcinoma - Accounting for 50 percent of non-small cell lung cancers.
• Squamous Cell Carcinoma of the Lungs - Responsible for around 30 percent of non-small cell lung cancers.
• Large Cell Lung Cancer - Responsible for about 10 percent of non-small cell lung cancers.

Non-small cell lung cancers are found more commonly among women, whereas small cell lung cancers are more likely to be found in men. Of non-small cell lung cancers, lung adenocarcinomas occur more frequently in women, while squamous cell and large cell lung cancers are more likely to occur in men.

Both non-small cell and small cell lung cancers are linked with a history of smoking, though small cell lung cancer is associated more strongly with smoking. Non-small cell lung cancers are the form of lung cancer found more frequently in individuals who have never smoked. How else is lung cancer different in non-smokers?

Of non-small cell lung cancers, lung adenocarcinoma is the type most likely to be found in non-smokers. Squamous cell carcinoma less common than lung adenocarcinoma overall, but is more common in people who have smoked.

There is a theory that the addition of filters to cigarettes in years back may have affected the types of lung cancer found. Cancers such as small cell lung cancer and squamous cell lung cancer tend to occur in or near the largest airways and were more common before the addition of filters to cigarettes. When filters became commonly used in cigarettes, cancers found more in the periphery of the lungs such as lung adenocarcinoma became more common, It's thought that the carcinogens in tobacco smoke were deposited in the large airways before the advent of filters, but are carried much deeper into the lungs with the addition of filters.

Lung adenocarcinoma is the most common type of lung cancer in young adults — accounting for roughly 80 percent of these cancers. Young adults with lung cancer are much more likely to have a genetic predisposition to lung cancer and a higher likelihood of treatable mutations.

Non-small cell lung cancer tends to grow more slowly than small cell lung cancer and have a better prognosis.That said, long-term survival from either form of lung cancer is higher when found in the earlier stages of the disease.