What Is Non-Small Cell Lung Cancer (NSCLC)? A Plain-Language Guide
Non-small cell lung cancer (NSCLC) is the umbrella term for the roughly 80-85% of lung cancers that are not small cell lung cancer, and it includes several subtypes, most commonly adenocarcinoma and squamous cell carcinoma.
NSCLC is diagnosed based on how cancer cells look under a microscope. The two largest subtypes are adenocarcinoma, which begins in the cells that produce mucus and now represents the most common lung cancer type in many countries, and squamous cell carcinoma, which begins in the flat cells lining the airways. A smaller share of cases are classified as large cell carcinoma.
NSCLC is typically slower-growing and spreads later than small cell lung cancer, which is part of why the two categories are treated as fundamentally different diseases in research and in clinical practice, despite both originating in lung tissue.
Genomic testing at diagnosis increasingly identifies specific driver mutations within NSCLC โ such as EGFR, ALK, KRAS, ROS1, and MET exon 14 โ that can be targeted with specific therapies. You can see current trial volume across several of these categories on our live Research Progress Tracker.
Frequently Asked Questions
Is NSCLC one disease or several?
It's an umbrella category containing several distinct subtypes and, increasingly, distinct molecular subgroups defined by driver mutations.
What percentage of lung cancers are NSCLC?
Roughly 80-85% of lung cancer diagnoses are classified as non-small cell lung cancer.