Almost two thirds of women now diagnosed with breast cancer are likely to survive for at least 20 years, Cancer Research UK experts predict.
Women aged between 50 and 69, who are most likely to be diagnosed with the disease, have an even better prognosis, with 72% surviving for 20 years.
The figures for England and Wales are a vast improvement on a decade ago.
Then, women overall had a 54% chance of surviving for 10 years and a 44% chance of surviving for 20.
The report has been compiled by Cancer Research UK epidemiologist Professor Michel Coleman, who analysed data from the Office for National Statistics on breast cancer diagnoses between 1971 and 2001.
This was linked to mortality data for these women up to the end of 2003 to predict long-term breast cancer survival among women who were diagnosed recently.
Almost 80% of women aged between 50 and 69 will survive at least 10 years, the report predicts.
Data from the early 1990s shows just 59% of women in that age group survived for 10 years after breast cancer diagnosis.
And just 48% survived for 20 years or more.
Professor Coleman said survival rates for younger women were also set to improve - though trends would improve less dramatically than in older age groups.
In the early 1990s, women diagnosed before the age of 50 had a 60% chance of surviving for 10 years and a 50% chance of surviving for 20 years.
Those survival rates are predicted to increase by between 13% and 14% to 73% and 64% respectively for women diagnosed during the first few years of this century.
Professor Coleman said: "Overall long-term survival for women with breast cancer has improved dramatically over the last 10 years and we are seeing even better survival statistics for women in their fifties and sixties."
Professor Tony Howell, Cancer Research UK consultant medical oncologist at the Christie Hospital, Manchester, said: "These results are highly encouraging for women who are worried about their cancer coming back.
"They will also encourage women to go for mammography since women with screen detected cancers fare particularly well."
Dr Richard Sullivan, director of clinical programmes at Cancer Research UK, said: "This is the first time we have been able to predict such a huge improvement in long-term survival figures."
He added: "Women diagnosed today have a much brighter future than those who faced breast cancer a generation ago.
"Detection rates have certainly increased as a result of the breast screening programme.
"And breast cancer treatments have improved enormously thanks to the success of cancer research - so much of which is funded through the generosity of the public."
Dr Sarah Rawlings, head of policy at Breakthrough Breast Cancer, said: "If we want to improve these survival rates even further then rapid access to diagnosis and treatment are key but ultimately what we'd really like to see is breast cancer becoming a preventable disease."
Anna Wood, of Breast Cancer Care, added: "It is also essential that women over the age of 50, who are eligible for breast screening, take up opportunities for regular checks."
Professor Mike Richards, the government's cancer tsar, said: "Continued investment in staff and equipment combined with reforms to the way we work will mean that breast cancer services will improve even further in the future."