pulmonary disorders
Lung Carcinoma
Classification of Lung Carcinoma
Lung cancer is classified into 2 major categories: Small cell lung cancer (SCLC), about 15% of cases Non–small cell lung cancer (NSCLC), about 85% of cases SCLCis highly aggressive and almost always occurs in people who smoke. It is rapidly growing, and roughly 80% of patients have metastatic disease at the time of diagnosis. The clinical behavior ofNSCLCis more variable and depends on histologic type, but about 40% of patients will have metastatic disease outside of the chest at the time of diagnosis. Oncogenic driver mutations have been identified primarily in adenocarcinoma, and attempts are being made to identify similar mutations in squamous cell carcinoma (eg,KRAS,EGFR,FGFR1,DDR2,PIK3CA). Other features of the 2 categories (eg, location, risks, treatment, complications) also vary (see table). 