The most common types are named for how the lung cancer cells look under a microscope:

Small cell lung cancer: About 13 percent of lung cancers are small cell lung cancers. This type tends to spread quickly.

Nonsmall cell lung cancer: Most lung cancers (about 87 percent) are nonsmall cell lung cancers. This type spreads more slowly than small cell lung cancer.

The pathologist checks the sputum, pleural fluid, tissue, or other samples for cancer cells. If cancer is found, the pathologist reports the type.

Educational information provided by The National Cancer Institute (NCI) Internet site.