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Evaluation of tissue sampling methods used for MRI-detected contralateral breast lesions in the American College of Radiology Imaging Network 6667 trial.

OBJECTIVE
The purpose of our study was to evaluate tissue sampling methods used for MRI-detected suspicious contralateral breast lesions in the American College of Radiology Imaging Network (ACRIN) 6667 trial.


MATERIALS AND METHODS
Breast MRI was performed at 25 institutions in 969 women who had a recent diagnosis of unilateral breast cancer and negative contralateral mammography and clinical breast examinations. Biopsy was recommended for MRI findings in 135 women, and 121 underwent sampling. Frequencies and positive biopsy rates of sampling methods used for initial diagnosis and imaging guidance techniques were calculated and compared.


RESULTS
Sampling yielded 30 malignant and 91 benign results. Initial sampling used needle biopsy in 88 of 121 (72.7%) and surgical biopsy in 30 of 121 (24.8%) women. Surgical biopsy was excisional biopsy in 28 of 30 (93.3%) and mastectomy in two of 30 (6.7%). The remaining three of 121 (2.5%) women underwent mastectomy, but it was not documented whether this represented initial tissue sampling. Of imaging-guided procedures, 56 of 106 (52.8%) used MRI; 49 of 106 (46.2%), ultrasound; and one of 106 (1.0%), stereotaxis. MRI-guided sampling was with needle biopsy rather than wire-localized surgical biopsy in 33 of 56 (58.9%) women, whereas ultrasound used needle biopsy in 47 of 49 (95.9%). Positive biopsy rates of sampling methods were 20.5% for needle biopsy, 46.2% for excisional biopsy, and 0% for mastectomy.


CONCLUSION
The majority of initial biopsies for MRI-detected contralateral breast lesions used needle biopsy rather than surgical biopsy. Contralateral surgery could have been avoided in most cases had needle biopsy been performed because most excisional biopsy and all mastectomy results were benign. MRI-guided biopsy was significantly more likely than ultrasound-guided sampling to use wire-localized surgical biopsy rather than needle biopsy.