Whether postoperative radiotherapy improves survival compared with surgery alone in patients with head and neck cancer remains unclear. This Practice Point commentary discusses the findings of a study by Kao et al. who used the Surveillance, Epidemiology, and End Results database to look for evidence of improved overall survival in patients with node-positive head and neck cancer. The analysis included 5,297 eligible patients who were treated with first-line surgery, of whom 4,307 (81%) received adjuvant radiotherapy. On multivariate analysis, adjuvant radiotherapy, age, primary tumor site, tumor and nodal stage were significant predictors of overall survival. While these results show an association between the use of adjuvant radiotherapy and improved overall survival in a selected group of patients, several aspects of the study limit its interpretation. Whether there is a causal relationship between postoperative radiotherapy and the observed overall survival benefit remains undetermined.