Impact of intensive multimodal treatment on the outcomes of patients with anaplastic thyroid cancer.

Abstract

6082 Background: Anaplastic thyroid cancer (ATC) is a rare and aggressive type of thyroid malignancy with very poor prognosis and outcome despite therapy. The rarity of this disease and the poor functional status of ATC patients limit the ability to conduct clinical trials, thus there is a lack of large, controlled trials to guide treatment and evaluate the benefit of combined modality therapy. Methods: The National Cancer Database (NCDB) was queried for patients diagnosed with ATC at age 18 or older between 2004 and 2018. After excluding patients with unknown number of treatment modalities, Charlson-Deyo score of 3 or more and patients lost follow-up, we split the cohort into three groups according to the number of treatment modalities they received. Treatment modalities include surgery, radiation, and systemic therapy. Then, we evaluated the overall survival (OS) between the three groups. We studied the OS using Kaplan-Meier estimates and multivariate cox regression analyses to evaluate factors associated with OS. Additionally, propensity score matching (accounting for age, gender, race, Charlson-Deyo score, and clinical M stage) was used for more robust results. Results: A total of 3,460 patients with ATC were included in the analysis, of which 1,472 (42.5%) either received one type of therapy or did not receive any therapy (group1), 1,092 (31.6%) received bimodal therapy (group 2), and 896 (25.9%) received trimodal therapy (group 3). We found that group 3 had better OS compared to group 1 and group 2 (median OS 9.1 months vs 1.7 months and 4.9 months, respectively with P < 0.001 for all). Propensity score matching yielded 896 patients in each group. We found that group 3 had better OS compared to group 1 and group 2 (median OS 9.1 months vs 1.9 months and 5.2 months, respectively with P < 0.001 for all). Same trend was found in subgroup analysis when we split the cohort according to the metastatic status; in M0 group (median OS was 10.4 months vs 1.9 months and 6.1 months, respectively with P < 0.001 for all), in M1 group (median OS was 5.9 months vs 1.4 months and 3.7 months, respectively with P < 0.001 for all). On multivariate analysis, group 1 and group 2 were associated with worse OS compared to trimodal treatment (HR 2.721; 95% CI: 2.466 - 3.002 and HR 1.434; 95% CI: 1.299 - 1.582, P < 0.001 for all). Conclusions: Patients with ATC who were treated with intensive trimodal therapy had statistically significant improvement in OS compared to patients who received less intense therapy. This survival benefit was observed in both metastatic and non-metastatic groups. While we acknowledge the limitations of this retrospective analysis, our results showed the critical role of intensive therapy approach in this aggressive malignancy.