This is very sad but not unexpected news.
Professor O'Brien, who was 57, led research into head and neck cancer in Australia and operated on hundreds of patients.
I know Dr O'Brien has spent some time in America and may have met with Brian Hill.
I and many others have read his book "Never say Die" which details some of his journey as a H&N surgeon.

http://livenews.com.au/news/cancer-surgeon-chris-obrien-dies-from-brain-tumour/2009/6/5/208908

http://www.harpercollins.com.au/books/9780732288099/Never_Say_Die/index.aspx

History Leukoplakia bx 8/2006 SCC floor mouth T3N0M0- Verrucous Carcinoma.
14 hour 0p SCC-Right ND/excision/marginal mandibulectomy 9/2006, 4 teeth removed, flap from wrist, trach-ng 6 days- no chemo/rad.
6 ops and debulking (flap/tongue join) + bx's 2006-2012.
bx Jan 2012 Hyperkeratosis-Epithelial Dysplasia
24cm GIST tumour removed 8/2013. Indefinite Oral Chemo.

1/31/16 passed away peacefully surrounded by family