Does preoperative magnetic resonance imaging beneficially alter surgical management of invasive lobular carcinoma?

The role of breast magnetic resonance imaging (MRI) in patients with newly diagnosed breast cancer remains controversial. The objective of this study is to determine the impact of preoperative breast MRI on patients with biopsy-proven invasive lobular carcinoma (ILC) initially deemed eligible for breast conserving therapy. We analyzed a prospective cohort study of patients with biopsy-proven ILC that consented to undergo preoperative diagnostic MRI at our institution. Data analysis of 20 patients accrued from January 2010 through January 2011 was performed. Outcome measures included discovery of occult lesions, need for additional biopsies, change in surgical management, and need for surgical reexcision. MRI found an additional cancer in 40 per cent of patients and increased extent of disease in one patient. MRI led to eight biopsies, for a pathologically confirmed true positive rate of 82 per cent [95% confidence interval (CI) 62-101%] and only two unnecessary biopsies. Preoperative MRI beneficially altered surgical management in 42 per cent of patients (95% CI 19-65%) without leading to unnecessary surgery, and only one patient required reexcision for positive margins (5.8%, CI -5.8-17.4%). In conclusion, preoperative MRI in patients with ILC can detect additional disease that was missed by conventional workup, allowing for better preoperative planning and more appropriate oncologic resection.