Breast cancer survivors face hidden costs of up to £12,000 a year despite the NHS being free at the point of care, a damning report has revealed.
Research from the University of Cambridge shows around a third of women living with the disease face financial problems long after treatment has ended.
For some, these costs follow them for the rest of their lives - in the form of lost working hours, childcare, travel expenses and barriers to insurance.
Building on research conducted by Macmillan Cancer Support and the Lancet Breast Cancer Commission, experts estimate these costs could amount to an additional £1,000 a month - and may last for decades, for as long as a woman is living with the disease.
Presenting the findings at the 15th European Breast Cancer Conference in Barcelona, Professor Charlotte Coles, clinical oncologist and chair of the commission, said: 'The bottom line is that the NHS is only 'free' at the point of care.'
'What we found is that there are huge unmet financial costs, many of which are exacerbated by a postcode lottery.
'Patients are often faced with more costs following a diagnosis, whilst being less able to work - whether that's because of the side-effects of treatment or a lack of support getting back to work.
'But what we're also trying to highlight is that there are other costs which can't be measured in terms of pound signs that are putting immense stress on these women and their families.'
In a major new report, researchers have set out six evidence-based recommendations aimed at supporting breast cancer survivors - from trust-led discussions about money worries to phased return-to-work schemes, automatic travel concessions and help with form-filling.
The authors of the new research, spearheaded by Imperial College London and The Institute of Cancer Research, are now calling on the Government to reassess its approach to breast cancer care, warning that without a coordinated national strategy, tens of thousands of women will continue to face substantial and unnecessary financial burdens.
Prof Coles added that there are inconsistencies in the availability of well-established support services, meaning that while some patients are offered the psychological help they need in a timely manner, the majority are not.
This is likely to be affecting both timely access to treatment and survivors' quality of life, she added.
Dr Patrick Kierkegaard, an implementation scientist at the Cancer Research UK Convergence Science Centre, who used the earlier research to build the six-point plan, said: 'Existing services are not good enough and often deepen the burden through unclear support rules, hard-to-find money advice and confusion between private care and the NHS.'
'Women should never have to choose between treatment and childcare, but unfortunately that is the reality when hidden costs are not linked to practical actions.'
He said that during the interview stage of the pilot, a young mother reported having to take her daughter with her to chemotherapy.
'She was lucky enough that there was a MacMillan nurse around who offered to look after her child - but again this places an added strain on already stretched services,' he added.
'What we have done is devise an action map clearly outlining six measures that are ready for feasibility testing, in an attempt to bring UK decision makers, doctors and cancer survivors together.'
Prof Coles added: 'As it stands, a lot of these women end up becoming their own case managers. So not only do they have to deal with the cancer itself and any post-treatment side-effects but they also have to chase down paperwork, contact insurers and dip into savings to make ends meet.
'So becoming a survivor in this case means that you've also picked up a second job in terms of just trying to live life again.
'I think we could do a lot in the NHS, but we do need more investment to make a system that is really reactive. At the moment that's the idea, but the reality is that it's not working everywhere as it should.'