Women diagnosed with early breast cancer can now be offered important information about prognosis according to the authors of research published in the June 18 issue of the Medical Journal of Australia.
One in ten Australian women diagnosed with non-metastatic breast cancer will go on to develop the metastatic form of the disease within 5 years – but if the cancer has spread to nearby lymph nodes or adjacent tissue, the risk rises to 1 in 6, according to Dr Sarah Lord from the NHMRC Clinical Trials Centre at the University of Sydney and coauthors.
The researchers studied 6644 NSW women diagnosed with non-metastatic breast cancer in 2001 and 2002 to determine how many went on to develop the metastatic form of the disease. They classified women with non-metastatic breast cancer into two groups: localised (those with nodenegative tumour confined to breast tissue) and regional (those with spread to regional lymph nodes or adjacent tissues).
The overall risk of metastatic disease for both groups was 10%, but for those with localised cancer, the news was much better: only 1 in 20 went on to develop metastatic breast cancer (MBC) within 5 years.
The authors said their findings showed that, in addition to underlying tumour biology, the spread of disease at diagnosis remained an important prognostic factor. “Clinicians can use these estimates to inform women with breast cancer about the average risks of developing MBC”, they wrote.
Those found to be most at risk of MBC were women aged less than 50 years and those living in areas of lower socio-economic status. Also, the chance of being diagnosed with metastatic breast cancer was highest in the second year after initial breast cancer diagnosis.
“This information may provide some reassurance for women who completed their primary breast cancer treatment more than 2 years ago and remain recurrence free”, the authors wrote.
Although the risk of developing MBC is one of the major concerns for women with a diagnosis of early breast cancer, very few population-based studies have examined MBC incidence in those with nonmetastatic breast cancer at initial diagnosis, the authors wrote.
In the same issue of the journal, MJA editor Dr Annette Katelaris wrote that the research provided “real world” data that would inform discussions between clinicians and women newly diagnosed with breast cancer.
Source :The Medical Journal of Australia