By Jane Elliott
Health reporter, BBC News
The book follows a fictional family dealing with cancer
How do you tell your young child that you, or your partner, has breast cancer?
Do you tell them about the disease, or just pretend that everything is alright?
That was the agonising dilemma facing consultant child psychiatrist Gillian Forrest when she was diagnosed with the disease in her early forties.
Despite her training, nothing had prepared Gillian about to how to talk to her young children, then aged five and seven.
"I was in a great state of anxiety about the children, how to tell them and what to say," she said.
"In the end I just told them that I had a bad lump that had to be taken out.
"Nobody asked if I had any problems with explaining what was happening to my children - everything was focused on my condition."
Dr Forrest, now 61, said her children had coped well thanks to an excellent support network but that nearly two decades later the trauma was still fresh in their minds.
"They still remember to this day their anxiety when I was in hospital. For them that was the most difficult time," she said.
"I found it difficult to talk to them at the time. I think when you are first diagnosed with a life-limiting illness you are just overwhelmed with anxiety - about yourself and the future. And for me the anxiety about the children was paramount.
"I needed surgery, chemotherapy and radiotherapy. I went through the whole gammet of treatment and am delighted to say it was all successful, but I did find it a difficult time and I felt there was something lacking for parents, like me, with life threatening illness."
Gillian and illustrator Sarah Garson have produced a book, 'Mummy's Lump', they hope will help others break bad news to their children.
The book, the first of its kind in the UK, is aimed particulary at helping children under six whose mothers have been diagnosed with breast cancer.
It has been launched by the charity Breast Cancer Care, which is issuing it free through its website and helpline.
Their book follows the lives of Jack and Elly as they learn of their mother's diagnosis and treatment for breast cancer, looking not only the diagnosis, but the practicalities of their mum's hospitalisation, such as who will do the washing.
Ilustrations show the children visiting their mother in hospital, running riot while their father does the housework, and playing with the bandana their mother wears to cover her hair loss caused by her treatment.
Dr Forrest's sons were young when she was diagnosed with cancer
Before writing the book, Dr Forrest, a senior research fellow at Oxford University, carried out a research project with more than 30 mothers with early breast cancer and their families to find out more about the children's needs during their mother's initial treatment for breast cancer.
She found that even the youngest children had a much greater awareness of cancer than their parents realised, regardless of what they had been told.
"Children are exposed to enormous amounts of information about breast cancer in ways we don't really appreciate," she said.
"Many of them have had grandparents and friends' parents that have had cancer.
"While they knew the word cancer, they were too young to pick up that breast cancer had a different prognosis to other types of cancer, but they were aware that cancer was a bad thing and were confused about it."
Antonia Dean, clinical nurse specialist for the Breast Cancer Care helpline, said the book would be filling an obvious gap.
"I think the book is absolutely great. Obviously working for the helpline we hear from people struggling to know how to explain breast cancer to their children," she said.
"What is nice about it is that it has lovely pictures so it is very accessible for young children, but it also has a very strong narrative.
"It goes through some of the things a woman might go through such as diagnosis, but deals with it in a very reassuring way.
"It looks at things such as 'who is going to pick them up from school?', the things that are very real to children, but not necessarily the things that adults might first think of."
Alison Raven, who also works for Breast Cancer Care, said the book was a real asset.
"Gillian's research, coupled with her own experience of breast cancer, meant that the book had a real strength, directly addressing the issues that families in this situation can face," she said.
"By following Jack and Elly's mum through the various stages of her experience, parents can refer back to the book as mum's treatment progresses."