RESUMO
BACKGROUND: The presence and detection of multifocal and multicentric disease significantly increases the risk of recurrence and changes the best therapeutic approach in patients with breast cancer. Mammography has low sensitivity to detect multiple malignant foci in patients with dense breast parenchyma. We prospectively evaluated Magnetic Resonance Imaging (MRI) as part of preoperative assessment. MATERIAL AND METHODS: Women with clinical and radiological suspicion of breast cancer and dense breast parenchyma (> 75% dense tissue) were included. All patients underwent mammography, ultrasonogram and MRI prior to surgery. Surgical specimens were used for the detection of multifocal and multicentric disease. Patients who required neoadjuvant chemotherapy or radiotherapy were excluded. RESULTS: Nineteen patients were evaluated. Histological diagnosis was confirmed in 14 patients, multifocal and multicentric disease was found in five and two patients, respectively. Sensitivity and accuracy to detect multiple malignant foci were 42 and 64%, respectively, for mammography plus ultrasound and 100 and 92% for MRI (p<0.05). CONCLUSIONS: MRI is more sensible and has a better accuracy than mammography plus ultrasound to detect both multicentric and multifocal breast cancer in women with dense breast parenchyma. MRI can improve preoperative assessment of breast cancer in this group of patients.