More than a million people in the UK who care for a loved-one with cancer are potentially missing out on vital support and benefits, according to research by a leading charity.
Macmillan Cancer Support said around half (49%) of the 1.1m people in the UK looking after someone with the disease receive no formal or informal support at all.
While only 5% have undergone a Carers' Assessment with their local authority - enabling them access to practical, emotional and financial support.
The charity said the statistics may explain why 46% of those caring for a loved-one with cancer experience mental health problems such as stress, anxiety and depression, and why one in eight suffer physical health issues such as sleep and digestive problems.
One in seven (15%) carers also face financial problems due to their caring commitments, according to the Ipsos Mori report for Macmillan.
These included increased travel costs and money issues caused by giving up work to care for their loved-one.
Ciaran Devane, Macmillan's chief executive, said: "Our research shows how unsupported cancer carers really are in the UK.
"Carers want to look after their family or friend with cancer - but it is often at the expense of their own mental or physical health.
"Cancer is no longer necessarily a death sentence and this means there is a growing need for people to care for their family member or friend with cancer. Often this is long-term care. But carers need support to cope with the significant demands of their role."
The charity called for health and social care professionals to raise awareness about Carers' Assessments so more carers receive the help they need and are entitled to.
The report, named More Than A Million, classed carers as those who provided more than five hours of care a week.
According to the data, 44% of those questioned had never heard of Carers' Assessments, which people are legally entitled to if they provide a substantial amount of care to someone on a regular basis.
The assessments are carried out by local authority officials to ascertain what help people need with caring and what services and support social services can provide.
Rebecca Guyott, 19, from Essex, and her sisters have been caring for their mother since she was diagnosed with bowel cancer in 2010.
They were not aware they could have been entitled to a Carer's Assessment or benefits.
Guyott said: "It was left to me and my sisters to look after her and as a carer I found it a big strain. At work I often had to leave the office because of the emotional stress.
"I'd get home and do all the cleaning, washing and cooking as mum could hardly stand, let alone do anything for herself.
"After just a week of this I slept so badly because of the worry and then could barely wake up the next morning to go into work and start all over again."