154 and smoking were outcome predictors,19 which were also found in the current study. Another prospective cohort study from 2009 investigated factors associated with swallowing problems as measured with the SWAL-QOL after curative RT in HNC (n=529), showed in their multivariate analysis that T3-T4 HNC tumors, bilateral irradiation, weight loss, oropharynx tumors, accelerated RT, and concomitant CRT were related to a worse outcome.7 Besides the factors bilateral irradiation and accelerated RT, which were not part of the current study, the factors are similar to those found in the current study with respect to eating duration. Another prospective cohort study (n=587) from 2016 found the following factors to be associated with less HNC symptoms: older age, higher education, private insurance, no current tobacco use, alcohol use, no comorbidities, early-stage cancer and no current feeding tube.31 No other studies reported a positive effect of older age regarding HNC symptoms. A cross-sectional study (n=52) investigating tumor site and RT technique in a multivariable regression analysis found that only tumor site was significantly associated with total SWAL-QOL score.26 Another cross-sectional study (n=110) in patients receiving RT or CRT found that advanced tumors, patients receiving CRT, use of a nasogastric tube, tracheotomy, and continuation of smoking and drinking alcohol decreased QOL.10 The effect of smoking on treatment outcome has been described in several studies, in which it is known that survival rates are lower and recurrence rates are higher in patients who continue to smoke in comparison to patients who stop smoking.39,40 In addition, smokers are at higher risk for treatment failure, disease recurrence, and development of second primary tumors.41 Smokers showed a poorer response to RT, and increased toxicity and side effects from RT.42 After surgery, smokers showed significantly higher rates of wound complications and general morbidity, and had an increased risk of infection.43 In the current study, patients who smoked at baseline reported more swallowing problems in comparison to nonsmokers. Smoking cessation may therefore not only be important for survival and disease recurrence, but may also reduce swallowing problems before and after treatment. Besides smoking, it is known that the frequency and severity of swallowing problems are more pronounced when patients lose weight pretreatment (possibly because of the tumor), and that swallowing problems increase when weight loss increases.21 These effects were also found in the current study, where patients who had lost weight at time of diagnosis experienced more problems in comparison to patients who had no weight loss prior to treatment. It is important that patients receive a nutritional assessment or even undergo placement of a feeding tube during treatment to maintain a healthy weight, and to minimize patient-reported problems in the long term.21,44