Targeted Therapies and Radiation for the Treatment of Head and Neck Cancer

Kim, Gwi Eon

Abstract

PURPOSE: The purpose of this review is to provide an update on novel radiation treatments for head and neck cancer. RECENT FINDINGS: Despite the remarkable advances in chemotherapy and radiotherapy techniques, the management of advanced head and neck cancer remains challenging. Epidermal growth factor receptor (EGFR) is an appealing target for novel therapies in head and neck cancer because not only EGFR activation stimulates many important signaling pathways associated with cancer development and progression, and importantly, resistance to radiation. Furthermore, EGFR overexpression is known to be portended for a worse outcome in patients with advanced head and neck cancer. Two categories of compounds designed to abrogate EGFR signaling, such as monoclonal antibodies (Cetuximab) and tyrosine kinase inhibitors (ZD1839 and OSI-774) have been assessed and have been most extensively studied in preclinical models and clinical trials. Additional TKIs in clinical trials include a reversible agent, CI-1033, which blocks activation of all erbB receptors. Encouraging preclinical data for head and neck cancers resulted in rapid translation into the clinic. Results from initial clinical trials show rather surprisingly that only minority of patients benefited from EGFR inhibition as monotherapy or in combination with chemotherapy. In this review, we begin with a brief summary of erbB- mediated signal transduction. Subsequently, we present data on prognostic-predictive value of erbB receptor expression in HNC followed by preclinical and clinical data on the role of EGFR antagonists alone or in combination with radiation in the treatment of HNC. Finally, we discuss the emerging thoughts on resistance to EGFR blockade and efforts in the development of multiple-targeted therapy for combination with chemotherapy or radiation. Current challenges for investigators are to determine (1) who will benefit from targeted agents and which agents are most appropriate to combine with radiation and/or chemotherapy, (2) how to sequence these agents with radiation and/or cytotoxic compounds, (3) reliable markers for patient selection and verification of effective blockade of signaling in vivo, and (4) mechanisms behind intrinsic or acquired resistance to targeted agents to facilitate rational development of multi-targeted therapy. Other molecular-targeted approaches in head and neck cancer were briefly described, including angioenesis inhibitors, farnesyl transferase inhibitors, cell cycle regulators, and gene therapy SUMMARY: Novel targeted therapies are highly appealing in advanced head and neck cancer, and the most promising strategy to use them is a matter of intense investigation.