The 33-year-old singer and father-of-two was diagnosed with a rare and incurable glioblastoma multiforme (GBM) brain tumour last summer, and was shocked to learn many drug treatments have been deemed too expensive for the NHS to offer.
Parker told the Chat2Amani podcast: "I don't want to beat around the bush about the NHS.
"I think they've been great but I think there's a massive improvement needed in treatment for brain tumours."
The Glad You Came singer revealed to 23-year-old host Amani Liaquat, who also has GBM, that he is currently paying for several drugs privately in a bid to prevent his tumour from growing.
Liaquat revealed her family raised £100,000 to buy a year's supply of a trial drug from Germany, and said she had felt awkward about asking people for money even though she could not afford the treatment herself.
Parker said: "People should never be in that position.
"That's the one thing I want to at least try and get out of this if we can – raising awareness for glioblastoma – is can we get better treatment on the NHS?
"Radiation and chemotherapy, that treatment hasn't changed in 20 years, it's shocking! There's got to be a better answer out there."
He added: "It drives me insane the world just evolves around money. There's drugs out there that can save people's lives, it's so frustrating."
Since his diagnosis Parker has had chemotherapy and radiotherapy, which have shrunk his tumour. But it is still there and cannot be removed.
Brain tumours kill more children and people under 40 than any other cancer, yet only 2% of the national investment into cancer research is allocated to brain tumour research.
Read more: Tom Parker making brain cancer documentary
Watch: Tom Parker talks about his cancer diagnosis