The 'decay' of brachytherapy use in tumors of the oral cavity: A population-based patterns of care and outcomes analysis from 1973 to 2012

We aimed to evaluate if use of brachytherapy (BT) is associated with improved survival in patients with oral cavity cancer who do not receive surgery and to analyze patterns of care.We queried the Surveillance, Epidemiology, and End Results database for patients who received radiation therapy for squamous cell carcinoma of the oral cavity between 1973 and 2012. Patients were grouped by treatment modality: external beam radiotherapy alone vs. external beam radiotherapy + BT. Surgical patients were excluded. Trends in BT utilization over the study period and patterns of care were analyzed. Propensity scores were generated, and a nearest-neighbor matching algorithm was used to balance the 2 groups. Cox regression modeling was used to estimate the effect of BT on overall survival. Sensitivity analysis was conducted to estimate the effect of unmeasured confounders on the analysis.Of 5,161 patients with squamous cell carcinoma of the oral cavity who received radiotherapy, 12% of patients received BT. The rate of BT use has decreased by 0.58% per year (p 0.001). Factors that predicted for omission of radiation therapy included age ≥ 65 years (adjusted odds ratio [aOR], 0.56; p0.001), regional nodal disease (aOR, 0.57; p0.001), and black race (aOR, 0.45; p0.001). Use of BT was associated with a decreased risk of death (hazard ratio, 0.75; p0.001).The use of BT is associated with improved survival in oral cavity tumors treated with definitive radiotherapy. Rates of BT utilization have declined by 0.58% per year and are currently very low.