About 85% to 90% of lung cancers are non-small cell lung cancer (NSCLC). About 10% to 15% are small cell lung cancer (SCLC), named for the size of the cancer cells when seen under a microscope.
There are 3 main subtypes of NSCLC.
- Squamous cell (epidermoid) carcinoma
- Large cell (undifferentiated) carcinoma
The cells in these subtypes differ in size, shape, and chemical make-up when looked at under a microscope. But they are grouped together because the approach to treatment and prognosis (outlook) are very similar.