Head and Neck Cancer
PV QA 2 - Poster Viewing Q&A 2
Purpose/Objective(s): Anaplastic thyroid carcinoma (ATC) is an uncommon malignancy with very poor prognosis and limited treatment options. Treatment of this highly aggressive disease is heterogeneous, in part due to patient-specific factors such as performance status but also scarcity of data comparing surgery, chemotherapy (CT), radiotherapy (RT), or combinations thereof. We aimed to compare survival between multi-modality treatment to less aggressive strategies using a large database.
Materials/Methods: The National Cancer Data Base was queried to capture patients with ATC diagnosed between 2004-2013. Those treated with either RT or CT was defined as single modality therapy (SMT). Those receiving both was defined as combined modality therapy (CMT). Overall survival (OS) defined as time from last treatment started to death or last follow-up. Survival was estimated using the Kaplan-Meier methods; distributions were compared using log-rank tests. Univariate Cox proportional hazards models were fit for each model variable: treatment group, surgery type, surgical margins, T, N, and M stage, tracheal extension, age, Charlson-Deyo (C-D) score, year of diagnosis, and RT dose. Propensity score matching (PSM) was used.
Results: 924 patients who received either RT, CT, or both were included. 575 patients (62.2%) received CMT. 349 patients received SMT of either RT (N=283, 30.6%), or CT (N=66, 7.1%). 27.6% of patients received definitive surgery, 36.1% had disease confined to the thyroid (T4a), 14.9% had tracheal extension, 58.5% had M0 disease, 79.4% received RT with total dose ≥30 Gy. The median age was 68 years, 77.8% patients had C-D score of zero. Among patients who received definitive surgery 1y-r OS was 39.6% vs 21.9%, and 5-yr OS was 22.3% vs 9.5% (CMT vs SMT, p=0.002); those with non-definitive surgery had 1-yr OS of 19.3% vs 13.9% (CMT vs. SMT, p<0.001). Benefits of CMT appeared confined to patients receiving radiation dose ≥30Gy with 1-yr OS of 28.6% vs 18.9% (p=0.001); when RT dose was <30 Gy, 1-yr OS was 6.1% vs 4.6% (p=0.17). A greater benefit to CMT was seen in patients with M0 disease: 34.2% vs 24.2% 1-yr OS (p=0.004); those with metastatic disease had 1-yr OS of 9.3% vs 5.3% (p<0.001). The magnitude of benefit to CMT vs SMT was similar between patients with T4a vs T4b disease. Combining all subgroup, CMT was associated with improved survival; 1-year OS was 25.5% vs 15.8% (CMT vs SMT, HR 0.69, log-rank p<0.001). A survival advantage to CMT was seen using PSM cohorts, with 1-year OS of 21.7% vs 15.9% (HR 0.79, log-rank p=0.01).
Conclusion: Combined-modality therapy is associated with superior OS in patients with ATC. Subgroups that saw the greatest benefit to CMT: patients receiving definitive surgery, RT dose ≥30 Gy, and those with M0 disease. These data may aid in optimizing patient selection for more aggressive treatment approaches.
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