The MONET - Study: MR Mammography of Nonpalpable Breast Tumors

• The absolute number of surgical procedures in women with nonpalpable malignancies will be compared between MRI group and control group. [ Time Frame: 2010 ] [ Designated as safety issue: No ]
  

• The number of large core needle biopsies that can be prevented because of a definite diagnosis as provided by MRI will be calculated. [ Time Frame: 2009 ] [ Designated as safety issue: No ]
  

Each year 7000 women present with nonpalpable suspicious breast lesions on mammography in the Netherlands. In the usual care situation, these lesions are detected by mammography and ultrasonography and pathologically characterized by analysis of large core needle biopsy material. In case of malignancy, these lesions are surgically removed. First, a wire is placed in the breast with the tip of the wire within 1 cm of the tumor and then the surgeon follows the wire and removes the lesion. Unfortunately about 25% of women require more that one surgical procedure to remove all tumorous tissue. This is caused by incorrect presurgical diagnosis of the extent and invasiveness of the disease (multifocality, multicentricity, lymph node involvement). We hypothesize that MR mammography will improve presurgical diagnosis and differentiation of lesions and thereby decrease the number of invasive surgical procedures (primary outcome) and number of invasive biopsies (secondary outcome).