Abstract P1-01-10: A preoperative PET/MR imaging for diagnosing malignant axillary lymph nodes in women evaluated for breast cancer

Abstract

Abstract Objective: We determined whether and how malignant node could be diagnosed preoperatively with simultaneous PET/MR imaging. Materials and methods:Two hundred thirty-six consecutive women with breast cancer were recruited to undergo preoperative PET/MR imaging. 52 patients were excluded; 31 DCIS, 7 neoadjuvant chemotherapy and 14 previous excisional biopsy. Thus, 184 women (51.9 ±10.2 years old) were included. Axial T1w without fat saturation, contrast enhanced image and diffusion-weighted images with simultaneous acquired PET images were analyzed by nuclear medicine physicians who were blinded the histologic findings. Visual FDG avidity, long axis and cortical thickness of axillary lymph node (ALN), morphologic feature-loss of fat hilum, cortical thickening, round shape or irregular shape- and ADC value were analyzed in most suspicious ALNs. Results:In total, 70 patients (15 patients have only micrometastasis) exhibited ALN metastasis. Mean size of breast mass was 2.1 ±1.5 cm. Macrometastatic ALN showed high FDG uptake, longer axis, thicker cortex, more frequent morphologic abnormalities, higher signal intensity at DWI and higher ADC values with statistical significance. No significant difference between micrometastatic ALN and benign ALN in PET/MR imaging. With pathologic diagnosis as the reference standard, the sensitivity, specificity and accuracy of PET for determining ALN metastasis were 84%, 58% and 68%, respectively. Those are 77%, 84% and 82% in considering both PET with morphologic change and 81%, 66% and 72% in considering PET, morphologic change and DWI, respectively. Conclusion:PET/MR imaging techniques showed high accuracy in the preoperative evaluation of axillary status in patients with breast cancer. Additional information by DWI is unlikely to be useful in predicting metastatic ALN. Citation Format: Kyung Jun Yeu, Jeong Yeong Park, Jung Eun Choi, Su Hwan Kang, Eun-Jung Kong, Ihn-Ho Cho, Soo Jung Lee. A preoperative PET/MR imaging for diagnosing malignant axillary lymph nodes in women evaluated for breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-01-10.