A new report by Rare Cancers Australia has uncovered a deadly discrepancy in the funding of cancer treatment and research in Australia that has left patients with rare and less common forms of the disease forced to self-fund treatment or go without.

The same proportion of Australians die from rare and uncommon cancers as common cancers, but the levels of funding for treatment and research are skewed.

Just 15 per cent of the total PBS cancer spend is allocated to rare and less common cancers whereas about 24 per cent is allocated to breast cancer alone.

Garvan Institute Professor David Thomas said the scale of this unmet need was too large to ignore and the essential problems lay with how cancer was classified.

"Our health system is geared to a nineteenth century model of cancer classification," he said.

"Such a dry topic as classification can have such far reaching consequences."

He said cancer was initially thought of as one disease, or affecting one organ, whereas in fact it is rather hundreds of different diseases that manifest differently in individual patients and therefore represents a health challenge of great complexity.

Geoff Olsson stopped counting the number of time he's gone under the knife after his 176th surgery.

The stoic father from rural South Australia has Gorlin Syndrome, a rare type of nevoid basal cell carcinoma syndrome.

Despite the punishing physical toll his diseases takes, he works full time managing TAFE facilities in Gawler and is a part time leader at his 15 year old son Simon's scout club.

Mr Olsson struggles to cover the prohibitive costs of his medication and said on three occasions has come close to losing his house.

"Bupa will only put $40 per month toward the cost of the $7,500 bill," he said.

Fundraising through www.sickortreat.org.au, receiving compassionate supply from drug manufacturers and financial support from family have been vital to keeping him going.

"The biggest thing would be getting drugs like mine on the PBS," he said. "The maximum payout I think then is about $2,500. Even if I had to pay that instead of what I do know it means three more months supply and taking the pressure of my dad who I think has dipped into his super."

Professor Thomas urged a federal government review into the way trials were developed, drugs were approved and prescribed for rarer forms of cancer to help mitigate the disadvantage shown in the report.

"Partly it's about recognising we have an enormous unmet need," he said.

"Things have changed so that we can do things about rare cancers, but we are stuck in a mindset that is limiting us to do so.

"We already know doing research into these less common diseases correlates with better outcomes.

"I think we should be expediting access to those neglected populations to the new drugs so they are not the last ones to benefit from the advances we make."