Association of Treatment Delays With Survival for Patients With Head and Neck Cancer: A Systematic Review.

Importance: Delays in the delivery of care for head and neck cancer (HNC) are a key driver of poor oncologic outcomes and thus represent an important therapeutic target. Objective: To synthesize information about the association between delays in the delivery of care for HNC and oncologic outcomes. Evidence Review: A systematic review of the English-language literature in PubMed/MEDLINE and Scopus published between January 1, 2007, and February 28, 2018, was performed to identify articles addressing the association between treatment delays and oncologic outcomes for patients with HNC. Articles that were included (1) addressed cancer of the oral cavity, oropharynx, hypopharynx, or larynx; (2) discussed patients treated in 2004 or later; (3) analyzed time of diagnosis to treatment initiation (DTI), time from surgery to the initiation of postoperative radiotherapy, and/or treatment package time (TPT; the time from surgery through the completion of postoperative radiotherapy); (4) included a clear definition of treatment delay; and (5) analyzed the association between the treatment time interval and an oncologic outcome measure. Quality assessment was performed using the Institute of Health Economics Quality Appraisal Checklist for Case Series Studies. Findings: A total of 18 studies met inclusion criteria and formed the basis of the systematic review. Nine studies used the National Cancer Database and 6 studies were single-institution retrospective reviews. Of the 13 studies assessing DTI, 9 found an association between longer DTI and poorer overall survival; proposed DTI delay thresholds ranged from more than 20 days to 120 days or more. Four of the 5 studies assessing time from surgery to the initiation of postoperative radiotherapy (and all 4 studies assessing guideline-adherent time to postoperative radiotherapy) found an association between a timely progression from surgery to the initiation of postoperative radiotherapy and improved overall or recurrence-free survival. Of the 5 studies examining TPT, 4 found that prolonged TPT correlated with poorer overall survival; proposed thresholds for prolonged TPT ranged from 77 days or more to more than 100 days. Conclusions and Relevance: Timely care regarding initiation of treatment, postoperative radiotherapy, and TPT is associated with survival for patients with HNC, although significant heterogeneity exists for defining delayed DTI and TPT. Further research is required to standardize optimal time goals, identify barriers to timely care for each interval, and design interventions to minimize delays.