Rationale and objectives: To evaluate the associations of patient age and clinical indication with the risk of malignancy for suspicious lesions initially detected on breast magnetic resonance imaging (MRI).
Methods and materials: After institutional review board approval, a retrospective review of our breast MRI database was performed to identify all nonpalpable, mammographically occult, MRI-detected suspicious lesions between January 1, 2003, and November 30, 2006, that underwent needle or excisional biopsy. Clinical indication and patient age were recorded and their associations with risk of malignancy were assessed using univariate and multivariate generalized estimating equations.
Results: The likelihood of malignancy was significantly higher (P = .0004) for suspicious lesions found on MRI examinations performed for a patient history of known cancer/evaluate extent of disease (130/309, 42%) compared to lesions identified on examinations conducted for high-risk screening (21/96, 22%). Suspicious lesions found in patients > or = 50 years of age were also more likely to be malignant (92/209, 44%) compared to those found in patients <50 years of age (59/196, 30%) (P = .004). In a multivariable model, both clinical indication of known cancer (OR 2.39, 95% CI 1.33-4.30) and age of 50 years or older (OR 1.66, 95% CI 1.03-2.68) were independently associated with greater risk of malignancy.
Conclusion: The clinical indication of known cancer/evaluate extent of disease and patient age of 50 years or older significantly increase the risk of malignancy in suspicious MRI-detected lesions.