Patterns of care and impact of brachytherapy boost utilization for squamous cell carcinoma of the base of tongue in a large, national cohort.

PURPOSE: The National Cancer Data Base was analyzed to evaluate the patterns of care and impact of brachytherapy (BT) boost on overall survival (OS) for patients with squamous cell carcinoma of the base of tongue.

METHODS AND MATERIALS: Patients with nonmetastatic squamous cell carcinoma of the base of tongue between 2004 and 2012 who received concurrent external beam radiation therapy (EBRT) and chemotherapy with or without BT boost in the definitive setting were queried. Overall survival was assessed by the Kaplan-Meier method. Cox regression analysis was used to identify covariates that affected OS.

RESULTS: There were 15,934 patients included in this study; 137 (0.9%) received EBRT + BT and the remaining received EBRT only. Median followup was 41.2 months. The utilization of BT boost declined from 2.1% in 2004 to 0.2% in 2012 (p < 0.0001), whereas intensity-modulated radiation therapy use increased from 22.8% in 2004 to 69.2% in 2012 (p < 0.0001). The three- and 5-year OS was 83.2% and 78.3% for patients receiving EBRT + BT compared with 77.4% and 69.0% for those receiving EBRT only (p = 0.03). The difference in survival was significantly better among patients with T3-4 tumors with EBRT + BT boost (p = 0.009) however, there was no survival benefit among patients with T1-2 tumors (p = 0.72). The analysis was repeated with patients who received intensity-modulated radiation therapy vs. EBRT with BT boost and the survival difference was sustained only for those with T3-4 tumors (p = 0.02).

CONCLUSIONS: Brachytherapy boost has decreased in its utilization even though it was associated with favorable survival outcomes particularly among patients with higher T-stage tumors.