US senator John McCain said doctors have given him a "very poor prognosis" as he battles brain cancer.

Mr McCain underwent surgery in July for a brain tumour that was later found to be a form of glioblastoma, the same type of cancer that took the life of his former US senate colleague Edward M Kennedy in 2009.

Mr McCain told CBS' 60 Minutes that he thinks about Mr Kennedy a lot.

The 81-year-old said Mr Kennedy continued to work despite his diagnosis, and "never gave up because he loved the engagement".

Arizona senator Mr McCain said he has "feelings sometimes of fear of what happens", but counters that with gratitude for having lived "a great life".

PA Media