OBJECTIVE: Stereotactic radiosurgery (SRS) is an effective therapeutic method to treat brain metastases (BM). A current debate considers BM dimension as an important issue regarding SRS therapeutic result. The aim of this study was to evaluate the dimensional progression of BM after SRS and identify factors related to patients and BM leading to local recurrence.
METHODS: Patients eligible for this study were those with BM from non-small cell lung cancer (NSCLC) who had been consecutively treated with SRS in 2010-2015. The dimensions of BM were measured by volume and greater diameter by nuclear magnetic resonance imaging (MRI) in T1-weighted contrast weighting using the Elements software (Brainlab). Dimensional data of BM were collected before the performance of SRS and after performing them during the follow-up of outpatients. After identifying the dimensions of BM in time progression, lesions that presented therapeutic success (reduction of BM dimensions) and local recurrence (growth of BM after SRS) were identified. Next, statistical evaluations were performed by statistical analysis at 12 months, considering epidemiological features presented by patients as well as topographic characteristics and radiological aspects of BM.
RESULTS: There was no correlation, after 12 months of the performance of SRS, between initial volume of BM and local recurrence. The results obtained identify a non-cystic BM, and brain left sided BM as elements related to higher progression free survival after 12 months of SRS.
CONCLUSION: Considering therapeutics in patients presenting BM, the correlation between initial volume and failure within 12 months after SRS had no statistical significance, BM located on the right side of the brain showed therapeutic fail within 12 months after SRS. Longer time of observation may be useful to confirm such results.