Cancer patients in Scotland are still facing a "postcode lottery" when it comes to accessing drugs despite a Scottish Government pledge to reform the system, according to Labour.

At her inaugural First Minister's Questions session at Holyrood, Nicola Sturgeon was challenged to explain when improvements which were due to be put in place in May will be brought forward.

The Scottish Government announced at the start of this year that Scotland's systems for approving and accessing new medicines for use in the NHS would see a "step change".

But Labour MSP Jackie Baillie - who is tasked with questioning the First Minister while the party's leadership contest takes place - said the changes had been delayed.

"It was promised in May," she told Ms Sturgeon. "The delay in introducing the new system for cancer drugs will be a lifetime to someone with a terminal illness."

She highlighted the case of Glasgow woman Jean MacDonald, who has had to pay £35,000 for drugs to treat ovarian cancer while the same drugs were prescribed to patients through the health service in Edinburgh.

"Can the First Minister tell me when she will end the postcode lottery for cancer patients across Scotland that her Health Secretary (Alex Neil) promised to happen by May?" Ms Baillie asked.

Ms Sturgeon, a former Health Secretary, said: "I want us to be working now to make sure that we do not have a postcode lottery, not just in this aspect of healthcare, but in any aspect of healthcare.

"I am familiar with the case she raises... I would be happy personally to speak to the individual in question, both to hear her experiences, which is the most important thing, but also to share with her the work that the Government is doing and intends to do in the future to improve the situation."

The Individual Patient Treatment Requests system (IPTR) was used by cancer sufferers to seek treatments not normally available for free in the NHS, but there was no uniform decision-making process across Scotland.

The Scottish Government announced that it would be replaced with a new peer-approved clinical opinion system (PACS) to tackle regional variation.

Ms Baillie said: "In October last year the Health Secretary did announce a new, more flexible system to give cancer patients access to the treatments they require based on clinical need, not based on where they live.

"And in January this year he said the new system would be introduced in May.

"May came and went. When questioned in July, the Health Secretary didn't answer, and earlier this year clinicians from the Beatson (cancer centre) came to this Parliament and said that the postcode lottery system continues despite the Health Secretary's promises."

Ms Sturgeon said she did not accept "the characterisation of delay".

"I want to deal with this issue as consensually as I possibly can, because I hope, while I absolutely respect Jackie Baillie's good faith in asking me the question, I hope she will respect my good faith in answering it, " she said.

"All of us across the chamber want to give people the best possible access to drugs and the best possible access to healthcare at their time of need."

Ms Sturgeon said the new Scottish Medicines Consortium (SMC) rules had been in place for some time. The SMC is the body which approves new drugs for use in the health service.

"This is not a closed book - there are some very complex and challenging issues around the decision-making process in terms of the allocation of drugs," she said.

"This Government has not shied away from that, so we will continue to make progress based on the discussions and the consideration that the Health Secretary has been making."

Ms Sturgeon said she was happy to meet with clinicians, cancer charities and patients.

"There will always be difficult decisions here, and it will not be possible under any circumstances to have a position where every single drug is always approved for use, but what I want to ensure is that we have confidence in the decision-making process."

Ms Baillie said Ms Sturgeon's comments were "completely at odds" with what cancer charities, clinicians and patients were saying is their "real experience of the system".

Ms Sturgeon said: "This is my first day in office, I could stand up here in response to any of the questions I am asked, and engage in the usual defensive ding dong... but today of all days, I want to make very clear, I am a new First Minister, I am a proud member of the Government for seven years. But I want to come into this job with an open mind and a willingness to hear proposals from all sides of the chamber."

She insisted the Government was working on the issue, adding: "On this issue, possibly above all other issues, it is important that we don't divide on party lines.

"These are matters of life and death for people."

Ms Baillie hit back, reading out comments from cancer sufferers, and asking: "When will this Government treat cancer patients in Scotland with the dignity and respect that we all believe they deserve?"

Ms Sturgeon said she would not be "provoked into a party political dispute on the issue".

She added: "I don't accept Jackie Baillie's characterisation of the performance and the position of the Government on this issue.

"When I was Health Secretary... as anyone who has been Health Secretary knows, you deal with some heart-wrenching issues.

"Access to drugs was probably the most heart-wrenching issue I ever dealt with. When you talk about losing sleep over issues, this one falls into that category.

"You know that no matter how many improvements you make to the processes, you will always have some cases where a patient, entirely understandably, thinks they should have access to a drug that for clinical reasons in particular they cannot get access to, and that is one of the most difficult things to comprehend when you are a politician.

"I am not standing here saying things are perfect, and I will work across the chamber to improve things, but politicians have a duty I think to recognise how difficult some of this is, and to recognise there will always be some difficult cases no matter how good the processes are."

A Scottish Government spokeswoman said: "We have radically overhauled drug access in Scotland for the better, bringing patient and clinician voice into the Scottish Medicines Consortium approval process for the first time. The Scottish Government is supporting this new approach through the New Medicines Fund, with £40 million available this year alone.

"Reforming the Individual Patient Treatment Requests (IPTR) system is one part of that process and we have put in place interim arrangements while we move to introducing the Peer Approved Clinical System (PACS). These interim arrangements have proved successful with a significant increase in the numbers and proportion of requests approved. So far in 2014, 92% of requests have been approved, compared with 66% in 2011/12.

"We want to ensure that the introduction of the PACS system does not negatively impact the number and proportion of approvals, so we will be carefully piloting the introduction of the PACS system to ensure there is no restriction in future access. The changes to the new SMC approach to approving medicines will also reduce reliance on individual requests."