Why is it called non-small cell lung cancer?

The term non-small cell lung cancer is used to classify different categories of lung cancer and was used initially to describe how cancer cells look under a microscope.

There are two primary types of lung cancer, known as non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). In a person with small cell cancer, the cancerous cells appear small and round under a microscope. The cells of non-small cell lung cancer are larger. NSCLC refers to any type of lung cancer that isn’t SCLC and the most common types of NSCLC are squamous cell carcinoma, large cell carcinoma, and adenocarcinoma.

85% of all lung cancers are NSCLC. Although this form of lung cancer progresses more slowly than SCLC, 40% of NSCLCs will have spread beyond the lungs by the time it is diagnosed. The most prevalent risk factor for NSCLC is smoking.