Radiation therapy dose is associated with improved survival for unresected anaplastic thyroid carcinoma: Outcomes from the National Cancer Data Base

BACKGROUNDThe outcomes of patients with unresected anaplastic thyroid carcinoma (ATC) from the National Cancer Data Base (NCDB) were assessed, and potential correlations were explored between radiation therapy (RT) dose and overall survival (OS). METHODSThe study cohort was comprised of patients who underwent either no surgery or grossly incomplete resection. Correlates of OS were explored using univariate analysis and multivariable analysis (MVA). RESULTSIn total, 1288 patients were analyzed. The mean patient age was 70.2 years, 59.7% of patients were women, and 47.6% received neck RT. The median OS was 2.27 months, and 11% of patients remained alive at 1 year. A positive RT dose-survival correlation was observed for the entire study cohort, for those who received systemic therapy, and for those with stage IVA/IVB and IVC disease. On MVA, older age (hazard ratio [HR], 1.317; 95% confidence interval [CI], 1.137-1.526),1 comorbidity (HR, 1.587; 95% CI, 1.379-1.827), distant metastasis (HR, 1.385; 95% CI, 1.216-1.578), receipt of systemic therapy (HR, 0.637; 95% CI, 0.547-0.742), and receipt of RT compared with no RT (<45 grays [Gy]:HR, 0.843; 95% CI, 0.718-0.988; 45-59.9 Gy: HR, 0.596; 95% CI, 0.479-0.743; 60-75 Gy: HR, 0.419; 95% CI, 0.339-0.517) correlated with OS. The RT dose-survival correlation for patients who received higher (60-75 Gy) versus lower (45-59.9 Gy) therapeutic doses was confirmed by propensity-score matching. CONCLUSIONSSurvival was poor in this cohort of patients with unresected ATC, and more effective therapies are needed. However, the association of RT dose with OS highlights the importance of identifying patients with unresected ATC who may still yet benefit from multimodal locoregional treatment that incorporates higher dose RT. Cancer 2017;123:1653-1661. (c) 2017 American Cancer Society. Correlates of overall survival and the correlation between radiation therapy (RT) dose and survival are studied in 1288 patients with unresected anaplastic thyroid carcinoma from the National Cancer Data Base. Higher RT dose is correlated with overall survival on propensity-score matching, which highlights the importance of identifying patients with unresected anaplastic thyroid cancer who may still yet benefit from multimodal locoregional treatment incorporating higher dose RT.