Mri Versus Breast-Specific Gamma Imaging (Bsgi) In The Detection Of Synchronous Breast Cancer: A Prospective Head-To-Head Trial

72 Background: Literature suggests that MRI identifies additional mammographically and sonographically occult cancers in 8-10% of newly diagnosed breast cancer patients. We have reported comparable sensitivity of BSGI to MRI in the detection of the known index cancer. We sought to prospectively compare BSGI to MRI in the identification of additional occult malignancies in newly diagnosed breast cancer patients. Methods: Patients with newly diagnosed breast cancer from June 1, 2009 through February 4, 2011 were consented for an IRB approved protocol in which they underwent both breast MRI and BSGI. Each imaging study was read by a dedicated breast radiologist, with one reading all MRI, and another reading all BSGI studies. All subsequent biopsies were performed percutaneously under image guidance and reviewed by dedicated pathologists. The identification of additional occult breast cancers by MRI and BSGI was compared. Results: Eighty-five patients underwent both MRI and BSGI. Twenty-one patients elected to undergo mastectomy without further management of imaging findings and were excluded, leaving 64 eligible patients. No additional lesions were found in 22 patients. Twenty-one patients had benign pathology on biopsied imaging findings. Metastatic axillary lymph nodes, satellite lesions or larger extent of disease was identified in 11 patients. Eleven occult breast cancers were identified in 10 patients (15.6%), 6 on MRI alone (9.4%), 3 on BSGI alone (4.7%), and 2 by both modalities (3.1%). There was no significant difference in the identification of occult cancer between MRI and BSGI (chi-square 0.77, p>0.1; Table). Conclusions: BSGI has previously been shown to be as sensitive as MRI for detecting known invasive and in situ breast carcinoma. This study shows that BSGI is equally sensitive to MRI in the detection of synchronous mammographically and sonographically occult cancers in newly diagnosed breast cancer patients. Further research is needed to identify the false positive rates of BSGI and the effect on surgical management in comparison to MRI. [Table: see text]