Laser interstitial thermal therapy (LITT) vs. bevacizumab for radiation necrosis in previously irradiated brain metastases.

PURPOSE: Both laser interstitial thermal therapy (LITT) and bevacizumab have been used successfully to treat radiation necrosis (RN) after radiation for brain metastases. Our purpose is to compare pre-treatment patient characteristics and outcomes between the two treatment options.

METHODS: Single-institution retrospective chart review identified brain metastasis patients who developed RN between 2011 and 2018. Pre-treatment factors and treatment responses were compared between those treated with LITT versus bevacizumab.

RESULTS: Twenty-five patients underwent LITT and 13 patients were treated with bevacizumab. The LITT cohort had a longer overall survival (median 24.8 vs. 15.2 months for bevacizumab, p = 0.003) and trended to have a longer time to local recurrence (median 12.1 months vs. 2.0 for bevacizumab), although the latter failed to achieve statistical significance (p = 0.091). LITT resulted in an initial increase in lesional volume compared to bevacizumab (p < 0.001). However, this trend reversed in the long term follow-up, with LITT resulting in a median volume decrease at 1 year post-treatment of - 64.7% (range - 96.0% to +  > 100%), while bevacizumab patients saw a median volume increase of +  > 100% (range - 63.0% to +  > 100%), p = 0.010.

CONCLUSIONS: Our study suggests that patients undergoing LITT for RN have longer overall survival and better long-term lesional volume reduction than those treated with bevacizumab. However, it remains unclear whether our findings are due only to a difference in efficacy of the treatments or the implications of selection bias.