Risk factors
Active or passive cigarette smoking is the major risk factor. One study found that cigarette smoking was associated with larger tumours than non-smoking at time of presentation[5].
Increased age.
People with chronic obstructive pulmonary disease. There may be explanations other than smoking (eg, genetic predisposition) for this association[6].
People with a previous history of cancer (especially head and neck)[7].
Industrial dust diseases, asbestos, chromium, arsenic, iron oxides and radiation.
The epidermal growth factor receptor (EGFR) and its ligands are frequently expressed in NSCLC and the EGFR tyrosine kinase (EGFR-TK) inhibitors erlotinib and gefitinib have shown clinical activity in the subgroup of patients with NSCLC who test positive for the EGFR-TK mutation[8].