Anaplastic thyroid cancer (ATC) is a highly lethal disease, often diagnosed with advanced locoregional and distant metastases, resulting in a median survival of just 3-5 months. This study determines the stratified effectiveness of baseline treatments in all combinations, enabling precise prognoses prediction and establishing benchmarks for advanced therapeutic options.The study extracted a cohort of pathologically confirmed ATC patients from the Surveillance, Epidemiology, and End Results program. Overall, 1879 patients from 2000 to 2018 were identified from the database. Kaplan-Meier survival curve estimation and Cox proportional hazard regression were applied.Overall, compared with no treatment, surgery raised 1-year overall survival (OS) from 0.6% to 30% and median survival from <1 month to 3 months in ATC patients. For stage IVa, surgery increased 1-year OS from 21.5% to 71.8% and median survival from 2 to 23.5 months, and in stage IVb, surgery increased 1-year OS from 9.4% to 41.3% and median survival from 2 to 7 months; however, in stage IVc, the benefits of surgery were not markedly different from non-surgical approaches. When combined with surgery, other effective non-surgical ATC treatments demonstrated a surgery-dominant synergistic effect, particularly for stages IVa and IVb ATC, but not for stage IVc ATC.Our study provides insights into stratified baseline treatments for patients with ATC in all stages, emphasizing surgery's vital role in a multimodal approach.© 2025. The Author(s).