BEAT-Breast: Trial of DE-iPTV in Patients With Primary Breast Cancer With Brain Metastases Who Are Not Suitable for Stereotactic Radiotherapy.

The aim of this study is to demonstrate if it is possible to delivering a novel and modern radiotherapy approach (Dose Escalated internal PTV (DE-iPTV)) and to collect health related quality of life in patients whose breast cancer has spread to the brain (brain metastases) at 8 weeks post enrolling into the study.

The main questions that have been set out to to answer are:

* Is it possible to deliver the novel radiotherapy approach, DE-iPTV?
* Is it possible to measure health -related quality of life?
* What impact does the novel radiotherapy approach have on: patient's quality of life, control of the brain metastasis (control of the lesion) and steroid use?

Participants will:

* Receive 5 doses of radiotherapy
* Complete weekly quality of life (EQ-5D) assessments and medication (steroid) diaries (via telephone/ postal) until 12 weeks post enrolment
* Be reviewed in clinic with up-to-date MRI scans at 8, 12 and 24 weeks post-enrolment
* Complete a more detailed HRQoL panel of assessments will be assessed at baseline, 8 weeks, 12 weeks and 24 weeks post enrolment.