Simone Schrading MD, Presenter: Nothing to Disclose

Hans H. Schild MD, Abstract Co-Author: Nothing to Disclose

Christiane Katharina Kuhl MD, Abstract Co-Author: Nothing to Disclose

In asymptomatic women at average risk, mammography, possibly amended by breast US is recommended for screening. Breast MRI is established for screening women at high familial risk, but there are no data available to support its use in women at average risk.

Between January 2005 and December 2010, 1162 women without personal or family history of breast or ovarian cancer, or diagnosis of atypias underwent 1482 annual breast MRI screening studies.  Mean / median age was 52 / 56 years, range 41-75. All women had normal CBE and normal double-read 2-view digital screening mammograms. Additional breast US was allowed in women with dense breasts, but women were included only if this US was normal. Patients underwent bilateral DCE breast MRI at 1.5T using a 2D GE pulse sequence. MRI studies were interpreted by two experienced breast radiologist in consensus. All suspicious lesions detected by MRI alone were clarified by MR guided vacuum biopsy.

A total 22 patients had positive MRIs (BI-RADS 4 or 5) (22/1482; 1.5%). Biopsies performed in these women were positive for breast cancer or DCIS in 8, and revealed high risk lesions in another 3 (papilloma in 1, LCIS in 2) patients. In 11 women, biopsy revealed benign changes only. This translates into a PPV of 36% (8/22), or 50% (11/22) if one includes the high risk lesions. Overall cancer detection rate was 5,4/1000. Of the total 8 women with cancer, 5 (63%) had invasive and 3 (38%) DCIS. Mean size of all invasive cancers was 9 mm (median 9, range 4 -13 mm). Invasive cancers were intermediate or high grade in 4/5, DCIS in 3/3. All patients were pN0, M0. Rate of minimal cancers was 6/8 (75%). Mammographic breast density in the 8 cancers was ACR 1 in 1 (12%), ACR II in 3 (38%), ACR III in 4 (38%), ACR IV in 1 (12%), equivalent to the distribution in the entire cohort.

In this cohort of women at average risk with normal screening mammograms and US, the additional cancer detection rate achieved through breast MRI was high (5.4/1000). Stage distribution of MRI detected additional cancers was favorable. Mammographic breast density did not predict the likelihood with which cancers were identified through MRI. PPV was comparable to that of mammographic screening programs.

MRI screening of women at average risk of breast cancer appears to be useful. The additional cancer detection rate is high, even in heavily pre-screened women.

Schrading, S, Schild, H, Kuhl, C, MRI Screening of Women at Average Risk of Breast Cancer.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12033351.html