Now she is part of a group of teachers helping to educate both adults and children and alleviate some of the fears surrounding the disease, which affects one in three people.
Mrs McKew is one of eight Barnet teachers who, along with a school nurse and the Cancer Research Campaign, have developed a pack designed to teach children about cancer.
The pack - Topic of Cancer - has been written for teachers by teachers, and is pitched at the four key stages of the national curriculum. It covers a range of subjects from the development and causes of cancer to prevention and treatment, and contains lesson plans for subjects including English, science, maths, and personal and social education.
"It's very much about putting positive messages across to the children rather than negative ones, because very often the only link children have with cancer is an extremely ill relative," said Mrs McKew.
"And while it is very important for children, it is equally necessary for staff. There was a time when I, like lots of people, found the word difficult to say. Now it trips off the tongue."
The schools pack emerged after a group of Barnet teachers met Dr Anne Charlton, the director of the Cancer Research Campaign's education and child studies research group.
Children were asking questions about cancer in the classroom which teachers were finding increasingly difficult to answer.
The pack not only contains lesson plans and worksheets, but also a question-and-answer booklet based on queries raised by children.
Mrs McKew, a teacher at Parkfield junior, middle and infant school in Hendon, said: "One of the children's questions that will always stick in my mind was can an ant get cancer."
The pack, developed over four years, has been funded by Barnet Health Agency, Europe Against Cancer, WH Smith's staff charity, Link-Up and Cancer Research.
Ironically, one of the teachers involved in the project - Judy Hudson, from St Michael's in Barnet - died of cancer in 1994. It has now been dedicated to her memory.
"Children are surrounded by cancer and by the myths and superstitions. They need to have them debunked and explained," said Wendy Bohm, a teacher from The Henrietta Barnet school.
Both Mrs McKew and Mrs Bohm believe work on cancer education needs to be done through a structured programme.
And Dr Charlton said: "We believe that cancer is an essential part of the school curriculum for four main reasons.
"First, we know that certain lifestyle habits reduce the risk of developing some forms of cancer and these habits start in childhood. Second, early detection offers the best chance of successful treatment.
"Third, many of these children have experience of cancer outside their classroom and by developing a better understanding of the disease and the hope offered by new treatments, the pack will promote more positive attitudes towards cancer patients.
"Finally, some children have fears and anxieties about cancer, just as many adults do - fears many teachers need help in addressing."
The pack, which has been piloted in Barnet schools, contains activities from dressing a cut-out doll for a sunny day to suggestions for designing a board game.
It contains interesting historical snippets such as evidence that dinosaurs suffered from cancer, and how in 1775 Dr Percival Pott made the connection between cancer of the scrotum and men who had worked as chim-ney sweeps when young - the culprit was soot.
Maggie Philbin, presenter on BBC TV's Tomorrow's World and Hospital Watch, said the project was thought-provoking and made for stimulating work. But she added: "Its significance goes way beyond the classroom. It could also be a lifesaver."
Three years ago, she discovered two lumps in her right breast and when told by her doctor that she needed surgery, burst into tears: "Despite my career in scientific and medical journalism, I didn't know where I stood or what to do next.
"I didn't hear his words or reassurance. I felt scared, ignorant and alone. If I'd had a few more facts at my disposal, I might not have been so afraid. "
Children from St Mary's primary in Finchley, who were at the launch of the pack at the Science Museum last week, were in no doubt too that they should be told about cancer.
And they were clear about a principal cause - smoking.
Eleven-year-old Tanya Chase urged pupils: "Don't smoke - just because your friends do it doesn't mean that you have to go along with it to look good. "
Puja Babbar, who had leukaemia three years ago at the age of seven, said: "Children should know more about cancer. It is important so that they know what to do."
The Topic of Cancer pack is available from the Cancer Research Campaign's Education Department, 10 Cambridge Terrace, London NW1 4JL, price Pounds 4.99.