Luca Alessandro Carbonaro MD, Presenter: Research Consultant, im3D SpA

Sara Vigano MD, Abstract Co-Author: Nothing to Disclose

Henrida Kule MD, Abstract Co-Author: Nothing to Disclose

Giovanni Di Leo, Abstract Co-Author: Nothing to Disclose

Francesco Sardanelli MD, Abstract Co-Author: Consultant, Bracco Group Research Grant, Bracco Group Consultant, Bayer AG Research Grant, Bayer AG Research Grant, IMS International Medical Scientific

To use morphologic and dynamic MRI features of the index lesion to predict ANS.

Seventy patients (median age 60 yrs) were studied at 1.5 T with axial STIR and axial or coronal T1w gradient-echo dynamic sequences (gadobenate dimeglumine, 0.1 mmol/kg). All index lesions were evaluated using morphologic and dynamic descriptors by one reader with 5 years of experience in breast MRI; lesion size at maximum intensity projection of subtracted images was recorded. ANS was defined on the basis of sentinel node biopsy (SNB) or axillary dissection. Correlation between lesion features and ANS was estimated using χ2 and Mann-Whitney U tests. Subsequently, considering only variables significantly correlated to ANS, we arbitrarily fixed the positive predictive value (PPV) and the negative predictive value (NPV) at 100% and retrospectively reconstruct the corresponding diagnostic tests (respectively SPIN and SNOUT test). Ultrasonographic (US) and MRI suspicious lymph nodes were registered and compared with the new diagnostic criteria obtained at 100% predictive values.

At pathology after surgical excision we had: 38 invasive ductal carcinomas (IDC), 7 invasive lobular carcinomas, 16 IDC associated with ductal carcinoma in situ (DCIS), and 9 pure DCIS. SNB was negative (N-) in 56 patients while 24 patients had axillary nodal metastasis (N+) at histopathology. The ANS was significantly correlated to lesion size (P=.002) and to dynamic curve type (P=.029). To a fixed 100% PPV, corresponded a diagnostic combined criteria of a lesions size > 30 mm and a type3 dynamic curve (4/24 lesions, 17%); all these patients had N+ with no suspicious features at US or MRI. To a fixed 100% NPV corresponded a diagnostic combined criteria of a lesions size ≤ 14 mm and a type-1 or 2 dynamic curve (10/46 lesions, 22%).

Using size and dynamic enhancement descriptors of the index lesion, 17% of N+ could be recognized and treated directly with axillary dissection saving cost and time for SNB while 22% of N- could be assessed as true negative without any surgical procedure.

Lesion size and dynamic enhancement descriptors can be used to predict ANS and avoid unnecessary sentinel node biopsy for both N+ and N- women in about 40% of patients.

Carbonaro, L, Vigano, S, Kule, H, Di Leo, G, Sardanelli, F, MRI Morphologic and Dynamic Features of Breast Cancer to Predict the Axillary Nodal Status (ANS).  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12025065.html