Sharp L, McDevitt J, Carsin AE, Brown C, Comber H. Smoking at diagnosis is an independent prognostic factor for cancer-specific survival in head and neck cancer: findings from a large, population-based study. Cancer Epidemiol Biomarkers Prev. 2014 Nov;23(11):2579-90. doi: 10.1158/1055-9965.EPI-14-0311