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.