Combination epidermal growth factor receptor inhibition and radical radiotherapy for NSCLC

Non-small cell lung cancer (NSCLC) remains the most common cause of cancer-related death in the developed world. Despite advances in therapy with conventional modalities, over 85% of patients will die from their disease within 5 years of diagnosis. For patients with inoperable lung cancer, the addition of chemotherapy to radical radiotherapy yields a small but significant 10% survival benefit at 3 years. However, the systemic toxicity of chemotherapy is common and may be severe. Over the past 20 years, dramatic improvements in our understanding of the molecular etiology of cancer have enabled the development of novel targeted therapies. Overexpression of the epidermal growth factor receptor (EGFR) in lung cancer correlates with an aggressive disease course and poor tumor response to radiotherapy. Strategies to inhibit this molecular switch have become a focus for drug development. Preclinical efficacy has been repeatedly demonstrated with anti-EGFR monoclonal antibodies and small molecule tyrosine kinase inhibitors, and responses have been documented in the clinic with acceptable toxicity. Phase III trials combining EGFR tyrosine kinase inhibitors with radical chemoradiation are recruiting at present. This review addresses the current challenges of discovering how best to use these new anticancer therapies, with particular emphasis on the enhancement of existing therapeutic strategies such as radical radiotherapy, factors relating to patient selection and prediction of clinical response.