Mr Medlicott, a Dunedin lawyer who chairs the trust, was among several speakers attending a function yesterday to launch the trust, at the Otago Museum.
The trust aimed to provide "better support for patients and their whanau", he said.
Another speaker, Dunedin neurosurgeon Ahmad Taha, highlighted the sudden onset of some brain tumours, which struck people without warning in the midst of successful careers.
"Everybody knows somebody who's died of a brain tumour," he added.
Despite the severe challenges, positive results could be obtained through surgery and other forms of treatment, but more research was needed, he said.
Mr Medlicott said the nation's hospital staff were doing their best, "but we keep hearing of cases of people who have no idea of what's going on" with their treatment.
"Hospitals are so siloed," he added.
Brain tumours were having a "massive effect" on individual patients and their families and the trust aimed to foster more "wrap-around" medical approaches and increase understanding of treatment, and also to support more medical research, including into glioblastomas, which were aggressive brain tumours.
A mother said an aggressive brain tumour had caused the death of "our beautiful little boy", and she believed the trust would help make a difference.
Health Minister David Clark had earlier unveiled the trust logo.
