Stereotactic radiosurgery for treatment of large cerebellum metastases from lung cancer

BACKGROUND Stereotactic radiosurgery (SRS) is an important treatment option. This report evaluated the efficacy and safety of SRS in patients with large cerebellum metastases from lung cancer. METHODS Between September 2016 and January 2020, a total of 44 patients with large cerebellum metastases >2 cm from lung cancer were evaluated. A median dose of 20 Gy (range, 8-24 Gy) was delivered in 1 to 3 fractions for SRS treatment. The survival rate was analyzed with SPSS software 21.0 and compared by log-rank test using the Kaplan-Meier method. RESULTS The median overall survival (OS) and neurological progression-free survival (PFS) were 10.5 months (range, 1-32 months) and 9.0 months (range, 1-32 months), respectively. The median diameter and volume of the metastases were 3.5 cm (range, 2.1-5.7 cm) and 12.5 cc (range, 1.8-39.7 cc), respectively. The median volume of peritumoral edema was 36.3 cc (range, 3.7-100.3 cc). The median ratio of tumor volume to cerebellum volume was 8.7% (range, 1.3-27.0%). The median ratio of peritumoral edema volume to cerebellum volume was 25.0% (range, 2.5-68.6%). Neurological symptoms were present in 97.7% (43/44) of patients. After SRS treatment, symptoms improved in 83.7% (36/44) patients, stabilized in 11.6% (5/44) patients, whilst two patients experienced symptomatic progression. Of the latter, one patient accepted emergency surgery and the other accepted palliative care. CONCLUSIONS Large cerebellum metastases are amongst the most severe forms of brain tumors. Increased tumor volume and peritumoral edema volume correlate with the most severe symptoms. SRS may be an effective alternative treatment for large cerebellum metastases from lung cancer and may preserve neurological function.