ORIGINAL ARTICLE Role of adjuvant chemoradiotherapy in T4N0 stage IV head and neck cancer: A National Cancer Database analysis Diana N. Kirke MBBS 1 | Muhammad M. Qureshi MBBS 2 | Sophia C. Kamran MD 3 | Waleed Ezzat MD 1 | Scharukh Jalisi MD 1 | Andrew Salama MD, DDS 4 | Peter C. Everett MD 5 | Minh Tam Truong MD 2 1 Department of Otolaryngology - Head and Neck Surgery, Boston Medical Center, Boston, Massachusetts 2 Department of Radiation Oncology, Boston Medical Center, Boston, Massachusetts 3 Harvard Radiation Oncology Program, Boston, Massachusetts 4 Department of Oral and Maxillofacial Surgery, Boston Medical Center, Boston, Massachusetts 5 Division of Hematology Oncology, Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts Correspondence Minh Tam Truong, Department of Radiation Oncology, Boston Medical Center, Boston University School of Medicine, 830 Harrison Avenue, LL237, Boston, MA 02118. Email: mitruong@bu.edu Funding information This work was presented in part at the American Head and Neck Society (AHNS) 9th International Conference on Head and Neck Cancer, Seattle, Washington, July 16-20, 2016. Abstract Background: The purpose of this study was to evaluate the role of postoperative adjuvant radiotherapy (surgery 1 adjuvant RT) versus adjuvant chemoradiotherapy (surgery 1 adjuvant CRT) in patients with T4N0M0, stage IV head and neck squa- mous cell carcinoma (HNSCC). Methods: Between 1998 and 2011, 3518 and 885 patients were treated with surgery 1 adjuvant RT and surgery 1 adjuvant CRT, respectively. Three-year overall survival (OS) rates were determined and crude and adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) were computed. Results: Median follow-up was 41.8 months with 2193 reported deaths. The 3-year OS was 67.5% for surgery 1 adjuvant RT and 70.5% for surgery 1 adjuvant CRT (P 5 .013). For negative margins, the corresponding 3-year OS was 70.1% and 74.9% (P 5 .005). For positive margins, the corresponding 3-year OS was 56.0% and 60.6% (P 5 .079). On multivariate analysis, the beneficial effect for adjuvant CRT over adjuvant RT was not significant (HR 0.90; CI 0.79-1.03; P 5 .124). Conclusion: In this cohort of patients with T4N0 HNSCC treated with surgery, there was no observed survival benefit of adjuvant CRT over adjuvant RT on multivariate analysis. KEYWORDS chemotherapy, head and neck cancer, radiotherapy, squamous cell carcinoma, survival 1 | INTRODUCTION Head and neck cancer, of which squamous cell carcinoma is the most common pathological subtype, accounts for 3% of all cancers in the United States. Every year, there are approx- imately 63030 new cases of head and neck cancer diagnosed in the United States. Despite improved surgical treatment of nodal disease and postoperative adjuvant treatment, there are still an estimated 13360 deaths from the disease yearly. 1 The treatment of resectable disease traditionally consists of surgery followed by adjuvant radiotherapy (RT) 1 /- chemo- therapy (surgery 1 adjuvant RT or surgery 1 adjuvant Head & Neck. 2018;1–11. wileyonlinelibrary.com/journal/hed V C 2018 Wiley Periodicals, Inc. | 1 Received: 3 August 2017 | Revised: 4 October 2017 | Accepted: 20 December 2017 DOI: 10.1002/hed.25087