To assess the impact of prophylactic treatment on the incidence of adverse events in advanced NSCLC patients (post chemotherapy) treated with dacomitinib daily as a single agent. To assess the impact of an interrupted dacomitinib dosing schedule in Cycle 1 on the incidence of adverse events in first-line advanced NSCLC patients with an EGFR mutation (HER-1 mutation, HER-2 mutation or HER-2 amplification).