Cancer patients are losing out due to huge variations in the costs of parking and travelling, campaigners say.
Parking charges varied across the UK
As part of a long-running campaign to force hospitals to scrap parking costs, Macmillan Cancer Support has criticised the postcode lottery in charges.
A poll of 1,100 patients found people in Scotland spent an average of £636 on parking and trips to hospital during treatment, compared to £318 in Wales.
The charity said parking should be made free and travelling subsidised.
AVERAGE TRAVEL COSTS DURING TREATMENT
Scotland - £636
South west - £477
South east - £424
North - £371
Midlands / East - £371
Wales - £318
The Macmillan survey found nine in 10 cancer patients incurred costs or experienced a loss in income following cancer diagnosis.
However, despite this only a fifth received any help towards travel costs - most of it from charities.
Macmillan chief executive Peter Cardy said: "These regional variations are shocking and grossly unfair - cancer patients in Scotland and the South West can pay almost double the costs.
"Missing an appointment is not an option for cancer patients - they have no choice but to pay for travel and parking, which amounts to a stealth tax on illness."
The charity said the problem was worsened by the fact that cancer patients already face potentially huge costs in prescription charges.
There is a subsidy scheme to recoup travel costs, but it is means-tested meaning only about one in 20 receive it.
The charity said cancer patients should be entitled to free parking and financial assistance from the hospital travel costs scheme.
It pointed out that due to the nature of cancer, patients make an average of 53 trips to hospital.
Valerie Penfare, a breast cancer patient from Bedfordshire, who has spent £1,000 going to Cambridge's Addenbrooke's Hospital in the last three years, said: "I am lucky, I have a good pension and have been able to afford the costs.
"But I have heard of people who have had a real struggle. It is so unfair to have to deal with this on top of fighting the disease."
Gill Morgan, chief executive of the NHS Confederation, which represents hospital managers, said parking charges were used to deter shoppers and commuters from using hospital car parks.
"It is not as straightforward as it seems to abolish all car parking charges. Some NHS hospitals have a very limited supply of car parking and are unable to provide free parking for all patients, which is why charges are used as a way of managing demand."
And she added many hospitals offered free or reduced rate car parking to patients.
The Department of Health said it was up to local hospitals to decide what it charges for parking.