The goal of this prospective, multi-center, randomized double-arm clinical trial is to demonstrate a benefit in term of local control of a shorter spread of hypofractionated stereotactic radiotherapy at D1-2-3 vs D1-3-5, in the treatment of "radioresistant" Brain Metastases (BM). This trial aims to recruit patients with 1 to 5 unoperated BM originating from radioresistant primary sites. Patients will be randomly assigned to either the D1-3-5 radiotherapy arm or the D1-2-3 radiotherapy arm. Stereotactic brain irradiation will be administered at a dose of 33 Gy delivered in 3 fractions.