According to a study published in theMedical Journal of Australia, important information regarding prognosis can now be given to women who are diagnosed with early breast cancer.
Dr Sarah Lord from the NHMRC Clinical Trials Center at the University of Sydney and her team note that in Australia, 1 in 10 women diagnosed with non-metastaticbreast cancer will develop metastatic cancerwithin five years. However, this figure increases to 1 in 6 women if the cancer has metastasized to adjacent tissue or nearby lymph nodes.
The researchers set out to determine how many women diagnosed with non-metastatic breast cancer develop the metastatic form of the disease by examining 6,644 NSW women who were diagnosed between 2001 and 2002.
The women were classified into two groups:
Localized - women with nodenegative tumor confined to breast tissue
Regional - those with spread to adjacent tissues or nearby lymph nodes
Although the risk of metastatic disease was 10% for both groups, the researchers found that only 1 in 20 women with localized cancer subsequently developed metastatic breast cancer (MBC) within 5 years.
According to the researchers, the study findings show that, in addition to underlying tumor biology, the spread of disease at diagnosis continues to be a vital prognostic factor. They explain: "Clinicians can use these estimates to inform women with breast cancer about the average risks of developing MBC."
The team found that women under 50 years of age and those living in areas of lower socio-economic status had the highest risk of developing MBC. Furthermore, women were more likely to be diagnosed with metastatic breast cancer in the second year after initial breast cancer diagnosis.
The researchers said: "This information may provide some reassurance for women who completed their primary breast cancer treatment more than 2 years ago and remain recurrence free."