Breast imaging in the young: the role of magnetic resonance imaging in breast cancer screening, diagnosis and follow-up
Diagnosis of breast cancer in young individuals (younger than 40 years old) poses a real challenge to breast radiologists because their breast tissue is often denser than the breast tissue of older women. Magnetic Resonance Imaging (MRI) may be particularly helpful in such situations. The American Cancer Society (ACS) recommended breast MRI screening as an adjunct to mammography for: BRCA mutation carriers and their first-degree relatives; women with a lifetime breast cancer risk ≥20% to 25%; women with a history of chest radiation between ages of 10 and 30 years; and women with predisposing genetic syndromes. Currently, breast MRI demonstrates a high sensitivity in the range of 93-100%. As many benign lesions also show enhancement or other atypical features on MRI, the primary weakness of contrast enhanced MRI remains in its low specificity, reported to be in the range of 37-97%. Breast MRI is helpful in demonstrating the true tumor size initially, as well as identifying residual tumor following the completion of neo-adjuvant therapy. In general, sensitivities ranging from 61% to 86% for detecting residual disease have been reported. The absence of enhancement virtually excludes a recurrence and the presence of enhancement is very specific for tumor even in the radiated breast. MRI is also the preferred modality for assessment of the breast after re- constructive surgery. The role of Magnetic Resonance Imaging (MRI) in breast diagnosis will continue to evolve as technology improves and clinical experience with new techniques expands.