ammography is the primary imaging modality used for breast cancer screening and is the only imaging test shown to reduce mortality from breast cancer (1-3). Although effective, one major limitation of mammography is its limited sensitivity, especially in women with dense breasts. The sensitivity of mammography in young women with dense breasts is reported to be as low as 38%-50% (4,5).Breast MRI is known to be the most sensitive imaging modality to detect breast cancer. However, breast MRI is restricted to screening women at high risk and, more recently, women with a personal history of breast cancer and dense breasts or who are diagnosed before age 50 years primarily because of its high cost and limited availability (6-14). Contrast agent-enhanced digital mammography (DM)(CEDM) is a contrast agent-based imaging test performed by using a modified DM unit. Studies (15-18) have reported that CEDM had improved sensitivity and specificity compared with conventional mammography in the diagnostic setting. To our knowledge, only two studies have evaluated the use of screening CEDM. The first study ( 19) was a small study of 307 women that compared screening CEDM with breast MRI and found that both CEDM and MRI depicted cancers not seen at conventional mammography. A more recent study (20) evaluated the performance of screening CEDM in 611 women at intermediate risk. In that study, CEDM was more sensitive than standard DM, with the addition of contrast enhancement resulting in an incremental cancer detection rate of 13.1 of 1000. The overall cancer detection rate in that study was high, at 31 of 1000 (19 cancers in 611 women).CEDM has been offered as a screening test at our Comprehensive Cancer Center since December 2012. Referring physicians may order CEDM as an alternative screening examination to conventional mammography. CEDM is most commonly performed to screen women at intermediate risk such as women with a

OBJECTIVE The purpose of this study was to assess the prevalence of internal mammary node (IMN) adenopathy in patients with breast cancer and compare breast MRI and PET/CT for detection of IMN adenopathy. MATERIALS AND METHODS This retrospective study included 90 women who underwent MRI and PET/CT before neoadjuvant chemotherapy for clinical stage IIA through IIIA disease. MRI and PET/CT examinations were read independently by two readers trained in breast imaging and nuclear medicine. All patients underwent follow-up MRI at the end of chemotherapy, and 10 with hypermetabolic IMNs underwent follow-up PET/CT. Histology was not obtained. Women were considered to have IMN adenopathy when nodes seen on MRI or having standardized uptake value (SUV) greater than mediastinal blood pool decreased in either size or SUV (or both) after treatment. Features including lymphovascular invasion, tumor quadrant(s), and axillary adenopathy were compared between presence and absence of IMN adenopathy using Fisher’s exact test. Prevalence was determined on the basis of the percentage of patients with IMN adenopathy by either modality. The McNemar test compared the prevalence of IMN adenopathy on MRI to its prevalence on PET/CT. RESULTS Prevalence of IMN adenopathy was 16% (14/90) by MRI and 14% (13/90) by PET/CT (p = 0.317). After chemotherapy, IMN adenopathy resolved in 12 of 14 patients (86%). In two patients with poor responses in primary tumors, IMN adenopathy persisted, and both patients developed metastatic disease within 6 months. At 3 years, survival was significantly worse in patients with IMN adenopathy than in those without (85.7% vs 53.3%, respectively; p = 0.009). CONCLUSION In women with advanced breast cancer receiving neoadjuvant chemotherapy, prevalence of IMN adenopathy was 16%, equally detected by breast MRI and PET/CT. Identification of IMN adenopathy may affect treatment and provides prognostic information.

Breast MRI had a high sensitivity for PABC in our study population. MRI may play an important role in PABC because it changed the surgical management of 28% of patients.

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