Stereotactic Radiotherapy in Oligometastatic Brain Disease: a Randomised Phase III Study Comparing Hypofractionated Stereotactic Radiation Therapy (3*10 Gy) to the Historical Single-dose Radiosurgery (1*20 to 25 Gy) With Medico-economic Evaluation.

Brain metastases (BM) are a common systemic cancer manifestation which incidence increases. Therapeutic options include whole-brain radiotherapy (WBRT), surgery, and stereotactic radiosurgery (SRS). The concept of "oligometastatic" cerebral disease (oligoBM) has emerged and led to consider alternative approaches. The main challenge is to preserve neurological function and independence the longest as possible.

Stereotactic radiotherapy (SRT) has emerged as an alternative treatment modality for selected oligoBM patients. It allows to achieve the balance of tumour destruction and normal tissue preservation by precisely and accurately delivering a very high dose of radiation in one (SRS) or a few (HSRT) fractions to a limited, well-defined volume. However, no standard exists for decision-making between SRS and HSRT and this important question is being discussed in the recent literature.

HSRT appears particularly interesting, assuming the patient convenience of few fractions, the normal tissue sparing achieved through focal irradiation, and the improved normal tissue tolerance of high dose radiation through fractionation.

Common adverse effects of SRT are rare but can occasionally be serious, notably radionecrosis that may induce neurological deficits in patients. Although SRS is often less well-tolerated, it remains the mainstay of treatment.

To investigators knowledge, SRS and HSRT have not been prospectively compared.