RT Journal Article SR Electronic T1 Radiation to the Primary Tumor in Metastatic Anaplastic Thyroid Cancer JF In Vivo JO In Vivo FD International Institute of Anticancer Research SP 461 OP 465 DO 10.21873/invivo.12279 VO 35 IS 1 A1 TERESA AUGUSTIN A1 DMYTRO OLIINYK A1 JOSEFINE RAUCH A1 VIKTORIA FLORENTINE KOEHLER A1 CHRISTINE SPITZWEG A1 CLAUS BELKA A1 LUKAS KÄSMANN YR 2021 UL http://iv.iiarjournals.org/content/35/1/461.abstract AB Background/Aim: Metastatic anaplastic thyroid cancer is associated with a dismal prognosis. We evaluated outcome and prognostic factors in patients receiving radiation to the primary tumor in metastatic anaplastic thyroid cancer (ATC). Patients and Methods: All consecutive patients with metastatic ATC (n=20) undergoing irradiation between 2009 and 2019 for anaplastic thyroid cancer were investigated. Results: Median survival time and median progression-free survival were 2 (range=1-22) and 2 (1-20) months. In univariate analyses, surgery, concurrent or sequential chemotherapy and higher radiation dose escalation (>39 Gy) were correlated with longer overall survival (p=0.005, p=0.018 and p=0.038), respectively. Karnofsky performance status >70% showed a trend of longer survival time (p=0.062). Limited metastatic disease, surgery and concurrent/sequential chemotherapy are correlated with longer progression-free survival times (p=0.043, p=0.024 and p=0.039), respectively. Conclusion: Radiation to the primary tumor in metastatic anaplastic thyroid cancer is safe and offers durable local control. Treatment intensification including concurrent or sequential chemotherapy and radiation dose escalation were associated with longer survival rates and should be considered in selected patients with metastatic disease.