Suppression of unspecific enhancement on breast magnetic resonance imaging (MRI) by antiestrogen medication.

Aims and Background: The value of breast MRI may be impaired by unspecific enhancement. This may leave patients with difficult-to-assess breast tissue with an uncertain diagnosis. We examined whether this unspecific enhancement (which is mostly due to proliferative or hyperplastic changes of benign breast tissue) may be suppressed by antiestrogen medication.
Methods: In a trial of treatment, 10 peri- or postmenopausal patients who exhibited diffuse and/or focal enhancement on breast MRI before tamoxifen medication agreed to undergo a short-term tamoxifen treatment. MRI monitoring was performed 2, 4 and 8 weeks after onset of antiestrogen therapy (tamoxifen, 30 mg per day).
Results: Six patients showed a significant decrease of enhancement. Unchanged (n = 3) or increased (n = 1) enhancement was seen in 4 patients. One of the three patients with unchanged enhancement proved to have diffuse lobular carcinoma in situ.
Conclusions: Part of the unspecific enhancement seen on breast MRI can probably be suppressed by short-term antiestrogen medication.