A recent study evaluated survival outcomes after adhering to the National Comprehensive Cancer Network (NCCN) guidelines for time to initiation of postoperative radiation therapy in patients with head and neck squamous cell carcinoma, published in Cancer (online August 25, 2017; doi:10.1002/cncr.30939).
Current NCCN guidelines recommend initiating postoperative radiation therapy within 6 weeks of surgery for patients with head and neck squamous cell carcinoma. However, limited research has assessed this time-to-initiation standard and compared it alongside different time intervals.
Evan M Graboyes, MD, department of otolaryngology-head and neck surgery, Medical University of South Carolina, and colleagues conducted a study to determine the effects of NCCN guideline-adherent initiation of postoperative radiation therapy and multiple other time-to-postoperative radiation therapy intervals on the overall survival (OS) of patients with head and neck squamous cell carcinoma. Researchers reviewed the National Cancer Database for patients with such disease who underwent surgery and postoperative radiation therapy from 2006 to 2014 (n = 41,291).
Researchers used Kaplan-Meier survival estimates, Cox regression analysis, and propensity score matching to evaluate the effects of initiating postoperative radiation therapy within 6 weeks of surgery and different time-to-therapy intervals from survival. Comparison intervals analyzed included ≤ 4 weeks, within 4-5 weeks, and > 6 weeks.
After adjusting for covariates, researchers found that starting postoperative radiation therapy sooner than 5 to 6 weeks was associated with decreased OS (HR, 1.13; 99% CI, 1.08-1.19). Similar data were demonstrated in the propensity score-matched subset (HR, 1.21; 99% CI, 1.15-1.28).
Further comparisons showed that initiating postoperative radiation therapy before the recommended time interval was not associated with improved OS (HR for ≤ 4 weeks, 0.93; 99% CI, 0.85-1.02; HR for 4-5 weeks, 0.92; 99% CI, 0.84-1.01).
Researchers noted that increasing durations of delay beyond 7 weeks were associated with small, progressive survival decrements (HR, 1.09, 1.10, and 1.12 for 7-8, 8-10, and > 10 weeks, respectively).
The study’s findings led researchers to conclude that nonadherence to NCCN guidelines regarding the optimal time interval for initiating postoperative radiation therapy after surgery is associated with a decreased survival likelihood of varying degree.—Zachary Bessette