Borthwick was first diagnosed with glioblastoma on 18 January after a week of persistent headaches that she initially blamed on the festive season’s exhaustion.
The aggressive tumour left her with a limited prognosis, and she spent the following months undergoing treatment while publicly sharing her journey to raise awareness of rare brain cancers.
During that time she joined the Brain Cancer Justice campaign, a group lobbying politicians for increased funding and support for patients with rare cancers.
A statement posted on her Instagram account on Tuesday, issued on behalf of her family, thanked supporters for the outpouring of love over the past eight months and confirmed that she passed away surrounded by her husband Ross and their sons Max and Freddie.
Borthwick’s death has reignited calls from the campaign and the wider rare‑cancer community for more research investment, highlighting the personal toll such diagnoses take on families.