Almost all women with early-stage breast cancer are now long term survivors.
Risk of death in the five years post diagnosis of early breast cancer has fallen from nearly 15% to 5% since the 1990s, UK research finds.
“Our study is good news for the great majority of women diagnosed with early breast cancer today because their prognosis has improved so much,” the authors wrote in the BMJ earlier this month.
The population-based observational cohort study used registry data from half a million women aged 18-89 with cancer confined to the breast, in some cases including axillary lymph nodes, who were diagnosed between 1993 and 2015.
All women were followed up until the end of 2020.
Researchers found that risk of death in the five years following diagnosis fell from 14% in the 1990s to 5% in the 2010s.
Annual death risk for most women increased in the two years following diagnosis, peaked in year three and then declined.
Mortality risk varied widely according to characteristics such as age, whether the cancer was detected by screening, presence of epidermal growth factor receptor 2, oestrogen receptor (ER) status, tumour size and grade and lymph involvement.
To provide data for guidance on prognosis, the authors calculated death risk by tumour grade, size, and positive nodes for different age groups of ER positive and negative women diagnosed between 2010 and 2015.
Over 60% of women had a risk of mortality within five years of diagnosis of 3% or less. Fewer than 5% of women had greater than 20% risk. Those at highest risk were adults aged 71 and over with HER-negative disease, high grade tumours over 50mm and over 10 positive nodes.
Before 2005, when only 50-64 year olds were eligible for screening, around 15% of tumours were screen-detected. This rose to 30% when screening expanded to include 65-70 year olds in 2005-2015.
Node negative disease increased from 45% in 1993-1999 to 65% in 2010-2015, signifying improved prognosis.
Praising the reliability of the large data set, Professor John Boyages AM, radiation oncologist at the Icon Cancer Centre, spoke of the hope this paper provides.
“Most people beat breast cancer and I think that is an important message,” he said.
“The important thing is that breast cancer is not an emergency. You’ve got time to dot the Is and cross the Ts. You’ve got time to read information.”
However, Professor Boyages warned of the “broad brush groupings” used in some of the statistical analysis for the 2010-2015 group that the authors suggested may assist in prognosis.
“Disparities are much more complex than you might think,” he said.
“Today, we’re better at crafting the right treatment for the right patient because we don’t rush into treatments,” he said.
The increase in molecular profiling has greatly aided prognosis. And awareness was also a major contributor to the reduction in mortality, along with improved screening technology, Professor Boyages said.
“We’ve got better quality mammography, we’ve got magnetic resonance imaging, MRI scans of the breasts, we’ve got PET scanning and all these things can help us work out the best treatment for a patient.”
Professor Boyages flagged the important role of GPs in ensuring patients are informed to make appropriate choices, for example about mastectomy versus breast conservation, in encouraging screening and, beyond all, in providing hope.