August 10, 2007
The Irish Times

MRI Scans Better at Detecting Breast Cancer, Research Finds

By Dick Ahlstrom, Science Editor

MRI scans may provide a far more sensitive method for detecting early breast cancers than conventional mammography, according to new research.

Magnetic resonance imaging was almost twice as likely to identify early stage ductal breast cancer compared to mammography, the study by a research team at the University of Bonn in Germany found. Details of the research by Prof Christiane Kuhl and colleagues are published this morning in the Lancet.

The five-year study involved 7,319 women, and of these 167 were found to have ductal carcinoma in situ (DCIS), which affects the milk ducts in the breast. A proportion of DCIS cases, if untreated, will go on to develop dangerous invasive breast cancer, the authors note, hence the assumed benefit of early DCIS diagnosis.

The study showed that of the 167 cancer cases, 153 (92 per cent) were detected by MRI, while conventional mammography detected 93 cases (56 per cent). MRI scanning also proved much better at detecting the more aggressive or "high grade" DCIS, which was detected in 89 of the women in the study group. Of this total, 87 cases (98 per cent) of the high grade cases were spotted by MRI compared to 46 cases (52 per cent) using the X-ray based mammography.

"MRI detected significantly more cases of any grade of DCIS than did mammography," the authors write. They conclude that "there is reason to assume that MRI helps anticipate the diagnosis of lesions that, if left undetected, would progress to high grade invasive breast cancer".

In Ireland, breast cancer mortality is 15 per cent higher than the EU average, according to the Irish Cancer Society. It is the most common fatal cancer in women and the current incidence of 2,700 new cases each year is rising.

The authors note, however, that their results "are not representative of the regular mass screening setting and have to be interpreted with care". They also point out that their findings "are unlikely to be reproducible in a community breast imaging service at present", given the fact that few radiographers reading MRI scans could match the very high accuracy rates developed by those experienced in reading mammograms.

The chairwoman of the breast cancer advocate group Europa Donna Ireland, Christine Murphy Whyte, welcomed the findings but urged caution given that new technologies needed "very, very rigorous tests" to prove their value.