If doctors could not first screen for that gene, which is present in a quarter of breast cancer cases, the drug would be far less useful.

FORBES: Why Cancer Drugs Need Genetic Testing

Miriam had two breast operations to remove her cancer (removal of a quarter of her breast and then later a full mastectomy of the same breast) - a tumour that doctors say may never have gone on to cause her any problems.

BBC: Breast screening: For and against

They found that a generally positive outlook appeared to reduce the chance of breast cancer by a quarter.

BBC: Positive thinkers 'avoid cancer'