Hypofractionated stereotactic radiotherapy for challenging brain metastases using 36 Gy in six fractions

Stereotactic radiosurgery and hypofractionated stereotactic radiotherapy are standard treatments for brain metastases when they are small in size (at the most 3cm in diameter) and limited in number, in patients with controlled extracerebral disease and a good performance status. Large inoperable brain metastases usually undergo hypofractionated stereotactic radiotherapy while haemorrhagic brain metastases have often been contraindicated for both stereotactic radiosurgery or hypofractionated stereotactic radiotherapy. The objective of this retrospective study was to assess a six 6Gy-fractions hypofractionated stereotactic radiotherapy scheme in use at our institution for haemorrhagic brain metastases, large brain metastases (size greater than 15cm³) or brain metastases located next to critical structures.

Patients with brain metastases treated with the 6×6Gy scheme since 2012 to 2016 were included. Haemorrhagic brain metastases were defined by usual criteria on CT scan and MRI. Efficacy, acute and late toxicity were evaluated.

Sixty-two patients presenting 92 brain metastases were included (32 haemorrhagic brain metastases). Median follow up was 10.1 months. One-year local control rate for haemorrhagic brain metastases, large brain metastases, or brain metastases next to critical structures were 90.7%, 73% and 86.7% respectively. Corresponding overall survival rates were 61.2%, 32% and 37.8%, respectively. Haemorrhagic complications occurred in 5.3% of patients (N=5), including two cases of brain metastases with pretreatment haemorrhagic signal. Tolerance was good with only one grade 3 acute toxicity.

The 6×6Gy hypofractionated stereotactic radiotherapy scheme seems to yield quite good results in patients with haemorrhagic brain metastases, which must be confirmed in a prospective way.