How many main types of lung cancer are there?

There are two basic forms of lung cancer: small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC).

• Small-cell lung cancer (SCLC): Also known as oat-cell carcinoma, this form accounts for 10 to 20 percent of all cases. It is highly aggressive, tends to metastasize quickly, and is rarely found in individuals who have never smoked.123
• Non-small-cell lung cancer (NSCLC): This form accounts for the remainder of lung cancer cases and consists primarily of three specific types:23
  • Adenocarcinoma: The most common type in the United States, accounting for about 40 percent of all lung cancer cases.2
  • Squamous cell carcinoma: Also called epidermoid carcinoma, this type typically develops in the larger bronchi and accounts for 25 to 30 percent of primary lung cancers.2
  • Large-cell carcinoma: Comprising about 10 percent of cases, these tumors tend to grow rapidly, though there is some scientific debate regarding whether they constitute a distinct type or a group of unusual squamous cell carcinomas and adenocarcinomas.2