Senior cancer specialists last night called on the NHS to make a less invasive treatment for prostate cancer with fewer chances of side effects available to all patients regardless of where they live.

Although brachytherapy was approved by the Scottish Executive five years ago to be delivered from cancer centres in Glasgow and Edinburgh, doctors admit there could be difficulties with access.

Two patients claim they were not informed of the availability of the treatment north of the border and were forced to make their own arrangements for therapy in England.

One patient who was diagnosed with prostate cancer was Graham Robson, from Aberdeen. He was offered either a prostecomy or external beam radiation and was ready to undergo the surgery until he spoke to a friend.

When he learned about brachytherapy, he made a round trip of more than 1100 miles to Professor Stephen Langley's centre in Surrey Mr Robson, 53, said of the original treatment offered: "I was very concerned about the side effects and the fact I could be off work for up to eight weeks.

"It was a friend who had the same symptoms and diagnosis but was way ahead of me in terms of research who told me about brachytherapy."

Paddy Kelly, 53, an airline pilot living in Troon, was another patient diagnosed with prostate cancer in 2005 who arranged for treatment at the Surrey clinic.

Mr Langley, at St Luke's Cancer Centre in Guildford in Surrey, said he has treated patients from Scotland who claim they were unable to access the treatment north of the border.

Mr Langley, who heads the Prostate Brachytherapy Advisory Group, said: "We are calling for increased access to brachytherapy across the UK. We hope to eradicate the postcode lottery so that every patient can have access to it.

"Awareness needs to be improved so patients can make an informed choice. Prostate cancer is now the number one cancer killer for men in the UK.

"There is a clear disparity in the provision of brachytherapy for prostate patients across the UK. We are calling on healthcare purchasers and providers to improve access to brachytherapy fourfold in line with government expectations and patient choice.

"Also to create a better understanding of brachytherapy amongst healthcare commissioners and to empower patients to make an informed choice."

Dr Ian Gibson, chairman of the Westminster All Party Parliamentary Group on Cancer, said he supported the campaign.

He said: "People are entitled to get the best treatment if it is available. There is absolute frustration over this. The most similar famous case was herceptin where women had to go to court to get treatment.

"Nice (National Institute for Clinical Excellence) makes the decision and they may say this is the best treatment but local providers may not fund it for whatever reason."

Dr John Graham, oncologist at the Beatson Centre in Glasgow, said: "The only issue is whether or not there is equality of access, which is being looked at. There shouldn't be a problem as we treat around 100 to 120 patients a year and there is capacity.

"We have had patients from Aberdeen and the Highlands. There is no issue with funding in Scotland the way there could be in England.

"Mr Kelly was offered brachytherapy at the Beatson, why he chose Surrey I do not know."

Nicola Sturgeon, Cabinet Secretary for Health, said: "Brachytherapy is a highly-specialised form of treatment that is suitable for only a very small number of patients with prostate cancer.

"Treatment is available in Edinburgh and Glasgow. These were set up to provide treatment for men from across Scotland and totals around 100 patients a year. There is no evidence that available capacity is insufficient.

"A review of brachytherapy services is under way that will look at latest evidence and, looking to the future, any predicted increases in demand.

"This will ensure that appropriate steps can be taken to expand provision if that is required."

A spokesman for NHS Grampian said he had no idea why Mr Robson went to Surrey as their patients are referred to Edinburgh for treatment.