MRI scans can help women with high breast cancer risk
Mary Ann Benitez and Hugh Ip
Women at high risk of breast cancer could benefit from MRI scans, experts say, following an international study that found the scans are better at detecting small tumours than the more commonly used mammography.
But the more expensive magnetic resonance imaging scans can also lead to unnecessary biopsies - removal of tissue for testing - and unnecessary anxiety.
'For very dense breasts, mammograms may not detect some subtle cancers,' said Winnie Chu Chiu-wing, associate professor at the Chinese University's Department of Diagnostic Radiology and Organ Imaging.
'MRI will not be affected by the density of the breasts. It is possible there is an advantage in Chinese women for MRI screening of the breasts, especially as they have very dense breast tissues.'
But because MRIs were non-specific, they could lead to unnecessary biopsies and anxiety, she said, adding that the Hospital Authority was unlikely to call for mass screening of women because of the high cost of the scans.
New research released last month suggests MRI scans find nearly twice as many tumours as X-ray-based mammograms in women at high risk of breast cancer.
According to a report in the New England Journal of Medicine, 51 of 1,909 Dutch women studied over three years were found to have breast cancer. Of these, 32 were identified using MRI, including 22 that had not been visible on mammograms.
The Hong Kong experts agreed that MRI scans could be used in addition to mammograms to diagnose breast tumours in women who have a mother or sister who had breast cancer, or who carry the gene mutations BRCA1 and BRCA2. About 5 to 10 per cent of breast cancer cases in Hong Kong involve hereditary breast cancer.
Clinical oncology specialist Victor Hsue said it had been known MRIs were good for detecting small breast tumours. But until MRIs could overcome technical hurdles, such as difficulty in obtaining a biopsy, mammograms would still be the 'gold standard' for diagnosing breast cancer, he said.
Mammograms cost $800 on average at private clinics and $225 at the Department of Health's women's health centres, while an MRI scan costs about $5,000.
Khoo Ui-soon, an associate professor in the University of Hong Kong's Department of Pathology, said MRI screening could be cost-effective, especially as those who carried the genes were 85 per cent more likely to get cancer.