Clinical impact of molecular breast imaging as adjunct diagnostic modality in evaluation of indeterminate breast abnormalities and unresolved diagnostic concerns.

PURPOSE: Improvements in molecular breast imaging (MBI) have increased the use of MBI as adjunct diagnostic modality and alternative to MRI. We aimed to assess the value of MBI in patients with equivocal breast lesions on conventional imaging, especially in terms of its ability to rule out malignancy. METHODS: We selected patients who underwent MBI in addition to conventional diagnostics due to equivocal breast lesions between 2012 and 2015. All patients underwent digital mammography, target ultrasound and MBI. MBI was performed using a single-head Dilon 6800 gamma camera after administration of 600 MBq 99m Tc-sestamibi. Imaging was reported according to BI-RADS classification and compared with pathology or follow-up of ≥6 months. RESULTS: Of 226 women included, pathology was obtained in 106 (47%) and (pre)malignant lesions were found in 25 (11%). Median follow-up was 5.4 years (IQR 3.9-7.1). Sensitivity was higher for MBI compared to conventional diagnostics (84% vs. 32%; P = 0.002), identifying malignancy in 21 and 6 patients, respectively, but specificity did not differ (86% vs. 81%; P = 0.161). Positive and negative predictive value were 43% and 98% for MBI and 17% and 91% for conventional diagnostics. MBI was discordant with conventional diagnostics in 68 (30%) patients and correctly changed diagnosis in 46 (20%) patients, identifying 15 malignant lesions. In subgroups with nipple discharge ( N = 42) and BI-RADS 3 lesions ( N = 113) MBI detected 7 of 8 occult malignancies. CONCLUSION: MBI correctly adjusted treatment in 20% of patients with diagnostic concerns after conventional work-up, and could rule out malignancy with a high negative predictive value of 98%.

The clinical impact of molecular breast imaging in women with proven invasive breast cancer scheduled for breast-conserving surgery.

PURPOSE: To investigate the clinical utility of molecular breast imaging (MBI) in patients with proven invasive breast cancer scheduled for breast-conserving surgery (BCS). METHODS: Following approval by the institutional review board and written informed consent, records of patients with newly diagnosed breast cancer scheduled for BCS who had undergone MBI for local staging in the period from March 2012 till December 2014 were retrospectively reviewed. RESULTS: A total of 287 women (aged 30-88 years) were evaluated. MBI showed T stage migration in 26 patients (9%), with frequent detection of in situ carcinoma around the tumor. Surgical management was adjusted in 14 of these patients (54%). In 17 of 287 patients (6%), MBI revealed 21 proven additional lesions in the ipsilateral, contralateral breast or both. In 18 of these additional foci (86%), detected in 15 patients, malignancy was found. Thirteen of these 15 patients had ipsilateral cancer and 2 patients bilateral malignancy. In total, MBI revealed a larger tumor extent, additional tumor foci or both in 40 patients (14%), leading to treatment adjustment in 25 patients (9%). CONCLUSION: MBI seems to be a useful imaging modality with a high predictive value in revealing ipsilateral and bilateral disease not visualized by mammography and ultrasound. It may play an important role in delineating the extent of the index lesion during preoperative planning. Incorporation of MBI in the clinical work-up as an adjunct modality to mammography and ultrasound may lead to better selection of patients who could benefit from BCS.