The MONET - Study: MR Mammography of Nonpalpable Breast Tumors (MONET)

MR Mammography: Randomized Controlled Trial to Study Efficiency of MR Mammography in Reducing the Number of Invasive Interventions in Nonpalpable Suspicious Breast Lesions. The MONET - Study

The purpose of this study is to determine whether performing MRI of the breast will improve breast cancer management by reducing the number of biopsies and in case of malignancy allowing one-stage surgical excision of the tumor.

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).

The absolute number of surgical procedures in women with nonpalpable malignancies will be compared between MRI group and control group.

The number of large core needle biopsies that can be prevented because of a definite diagnosis as provided by MRI will be calculated.

Inclusion Criteria: patients with a nonpalpable, mammographically suspicious breast lesion (BI-RADS 3, 4 or 5) referred for large core needle biopsy 18 to 75 years Exclusion Criteria: previous breast surgery or radiation therapy of the breast less than 9 months before MR mammography pregnant or lactating claustrophobia or adiposity ( > 130 kg) general contraindications for MRI unable to maintain prone position for one hour medically unstable patients

Peters NH, Borel Rinkes IH, Mali WP, van den Bosch MA, Storm RK, Plaisier PW, de Boer E, van Overbeeke AJ, Peeters PH. Breast MRI in nonpalpable breast lesions: a randomized trial with diagnostic and therapeutic outcome - MONET - study. Trials. 2007 Nov 28;8:40. doi: 10.1186/1745-6215-8-40.