ORIGINAL ARTICLE Association between treatment delays and oncologic outcome in patients treated with surgery and radiotherapy for head and neck cancer Vasu Tumati MD 1 | Lawrence Hoang BS 1 | Baran D. Sumer MD 2,3 | John M. Truelson MD 2,3 | Larry L. Myers MD 2,3 | Saad Khan MD 4,3 | Randall S. Hughes MD 4,3 | Lucien Nedzi MD 1,3 | David J. Sher MD MPH 1,5,3 1 Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 2 Department of Otolaryngology, University of Texas Southwestern Medical Center, Dallas, Texas 3 Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas 4 Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 5 Department of Outcomes and Health Services Research, University of Texas Southwestern Medical Center, Dallas, Texas Correspondence David J. Sher, MD, MPH, Associate Professor, Department of Radiation Oncology, University of Texas Southwestern Medical Center, 2280 Inwood Rd, Dallas, TX 75235. Email: david.sher@utsouthwestern.edu Abstract Background: This study sought to determine the oncologic impact of delays to surgery, radiotherapy, and completion of therapy in patients with head and neck squamous cell carcinoma. Methods: The impact of biopsy to surgery (BTS) time, surgery to start of radiation time (STSR), and radiation treatment time (RTT) on locoregional recurrence (LRR), distant metastases (DMs), and cancer-specific mortality (CSM) was exam- ined. The cumulative incidences (CI) of LRR, DMs, and CSM were examined using Fine–Gray testing. Results: A total of 277 patients treated with surgery and adjuvant radiotherapy were analyzed. On multivariable testing, BTS >50 days was associated with DM (P = .03), whereas RTT and STSR were not. RTT >43 days was associated with LRR (P = .02) in patients with non-p16-positive-oropharynx cancer. Conclusions: An increase in DM appears to be the mechanism by which prolonged time to treatment initiation leads to worse overall survival. Prolonged RTT has the greatest impact on patients with non-p16 positive oropharynx cancers. KEYWORDS adjuvant radiation therapy, head and neck cancer, time to treatment initiation, treatment delays 1 | INTRODUCTION A recent National Cancer Database analysis revealed that the time to treatment initiation for patients with head and neck cancer has been increasing, which may be a complex func- tion of socioeconomic challenges and an increased treatment complexity, requiring additional time to plan. 1 Furthermore, increasing time to treatment initiation has been associated with worse overall survival. 2 Delays in the total time taken to deliver radiation therapy have also been associated with increased rates of local and regional progression. 3–5 How- ever, studies of time to treatment initiation have largely been performed on the national scale, in which important cancer- specific data are missing and thus the mechanism of inferior survival cannot be further elucidated. In this single institution retrospective study, we sought to determine the effects of delays in each step of treatment, including time from biopsy to surgery (BTS), time from sur- gery to start of radiation (STSR), radiation treatment time (RTT), and time from surgery to the end of radiation (total package time, TPT) on locoregional recurrence (LRR), dis- tant metastasis (DM), and cancer-specific mortality (CSM) on patients with resectable head and neck cancer treated with curative-intent surgery followed by adjuvant radiotherapy or chemoradiotherapy. Received: 15 January 2018 Revised: 31 May 2018 Accepted: 15 August 2018 DOI: 10.1002/hed.25457 Head & Neck. 2018;1–7. wileyonlinelibrary.com/journal/hed © 2018 Wiley Periodicals, Inc. 1