Submitted by Dr. Zenon W. Gruba, Australia
By Sarah Colyer, 12-Nov-2009
MORE than 40% of breast cancers detected since the BreastScreen program was introduced in Australia would not have been life-threatening if left untreated, research suggests.
Analysing data from the NSW Central Cancer registry, University of Sydney researchers determined that risk factors such as obesity, nulliparity and a period of heightened HRT use could not account for the massive jump in the number of invasive breast cancer cases since mammography screening became routine.
The detection of cancers that would not have caused harm is the most likely explanation, they concluded.
Annual breast cancer notifications for NSW women aged 50-69 rose from 140-200 cases per 100,000 women in the 1970s, to 250-300 cases per 100,000 women by 2001 when mammography screening was well-established.
Writing in the journal Cancer Causes Control (online), the authors said the “overdiagnosis of invasive breast cancer attributable to mammography screening appears to be substantial”.
As many as 42% of breast cancers detected in women aged 50-69 were unlikely to have led to premature death, they estimated.
The findings are consistent with a recent Danish study, which analysed data from five countries, including the NSW cancer registry’s data from Australia.
From: Cancer Causes and Control 2009; online.
A Re-Published Article for Members
From THE BRIDGE Newsletter of OIRF
Published December 2009
© Copyright Nov. 2009, Sarah Colyer