Deek MP, et al. - Non–small cell lung cancer (NSCLC) patients treated with definitive chemoradiation therapy (CRT) were examined, to determine the prognostic impact of missed chemotherapy administrations (MCA). Findings demonstrated a correlation of MCA with worse prognosis and increased mortality. Methods to reduce toxicity may improve administration of all chemotherapy doses and increase overall survival in NSCLC treated with CRT.