New study examines the evidence of disease spreading in some women after initial diagnosis
The study, which covered tens of thousands of women internationally found overall the risk of cancer spreading following early diagnosis in women under 35 ranged from 12.7 per cent to 38 per cent. Women aged 50 years or older had a risk of 3.7 per cent to 28 per cent.
Dr Elieen Morgan, from the International Agency for Research on Cancer said the difference in risk may be because “younger women have a more aggressive form of breast cancer or because they are being diagnosed at a later stage.”
She said: “Breast cancer is the most common form of cancer in the world. Most women are diagnosed when their cancer is confined to the breast or has only spread to nearby tissue. But in some women, the cancer will grow and spread to other parts of the body or come back in a different part of the body several years after the end of their initial treatment.
“At this point the cancer becomes much harder to treat and the risk of dying is higher.”
But she explained the number of people who develop what is called “metastatic breast cancer” is unknown because this data is not routinely collected by official bodies.
The research also suggested rates of cancer returning after an initial diagnosis and spreading to other organs had decreased since the 1970s and 80s. But some of the reduction in rates may be due to the time lag between first diagnosis of breast cancer and signs of it spreading.
Dr Shani Paluch-Shimon, director of the Breast Unit at Hadassah University Hospital in Israel was not involved in the research but said: “There has been a knowledge gap about how many people are living with advanced breast cancer around the world. This study is a step towards filling that gap.”
Around 2.3 million people are diagnosed with breast cancer each year globally, however this study was the first of its kind to investigate how many patients develop advanced breast cancer.