PRIMARY OBJECTIVES:
I. To assess the clinical complete response rate (CR) after concurrent lapatinib (lapatinib ditosylate) and radiotherapy in patients with locally advanced or locally recurrent breast cancer that is refractory to chemotherapy.
SECONDARY OBJECTIVES:
I. To evaluate the feasibility of assessing breast cancer stem cells (BCSCs) using flow cytometry and single cell gene expression profiling (SCGEP).
II. To determine the change in the proportion of BCSCs after combined modality therapy.
III. To evaluate the safety and efficacy of the combination of lapatinib and radiotherapy.
IV. To assess the pathologic complete response rate (pCR) in those undergoing surgical resection.
OUTLINE:
Patients receive lapatinib ditosylate orally (PO) once daily (QD) on day 1 until completion of radiation therapy. Beginning on day 7, patients undergo radiation therapy for 5-7 weeks.
After completion of study treatment, patients are followed up at 2-4 weeks and then at 6-12 weeks.
