Performance status and number of metastatic extra-cerebral sites predict survival after radiotherapy of brain metastases from thyroid cancer

Background/Aim: Patients with brain metastases from thyroid cancer are extremely rare. This study evaluated clinical factors for survival following whole-brain radiotherapy (WBRT) alone. Patients and Methods: In six patients, the following factors were analyzed for survival: Regimen of WBRT (5×4 Gy vs. 10×3 Gy), gender, age (≤55 vs. ≥56 years), Karnofsky performance score (KPS) (60% vs. 70-80%), number of brain lesions (2-3 vs. ≥4) and number of extra-cranial metastatic sites (one vs. more than one). Results: KPS 70-80% (p=0.036) and involvement of only one extra-cranial site (p=0.018) were associated with better survival on univariate analysis. On Cox regression analysis, KPS (p=0.14) and number of extra-cranial sites (p=0.14) showed trends for association with survival. In patients with KPS 70-80% and only one extra-cranial site, 6-month survival was 100%, no patient with KPS 60% and more than one extra-cranial site survived to 6 months. Conclusion: KPS and number of involved extra-cranial metastatic sites were associated with survival and may be helpful for individualizing therapy in patients with brain metastases from thyroid cancer.