We propose to combine lapatinib with RT alone in patients with locally advanced head and neck cancer who cannot tolerate chemotherapy. The main objective of the study is to determine the efficacy of combining concurrent radiation and lapatinib in terms of time-to-progression (TTP) in this group of patients. In addition, we will determine the 2-year locoregional control rate (LRC), progression-free survival (PFS) and overall survival (OS) in these patients. We will also evaluate the profile and frequency of late toxicity, specifically mucosal and dermatologic toxicity, of the combination of lapatinib and RT in patients with locally advanced head and neck squamous cell carcinoma (HNSCC).