Manuela Durando, Presenter: Nothing to Disclose

Dilip Giri, Abstract Co-Author: Nothing to Disclose

Merlin Gnanasigamani, Abstract Co-Author: Nothing to Disclose

Joseph Owen Deasy PhD, Abstract Co-Author: Nothing to Disclose

Elizabeth A. Morris MD, Abstract Co-Author: Nothing to Disclose

Sunitha Thakur PhD, MS, Abstract Co-Author: Nothing to Disclose

To measure apparent diffusion coefficient (ADC) values in malignant lesions and evaluate their relationship with classical and molecular prognostic factors and Oncotype Dx scores.

This HIPAA compliant retrospective study consisted 212 consecutive patients with known cancers who underwent 3.0T MRI with DWI (b=0 and 600 s/mm2) between Jan’ 2011and Jan’ 2013. Lesions < 0.8 cm, lesions undergoing neoadjuvant chemotherapy or suboptimal DW images were excluded. ADC was analyzed on 148 malignant lesions in 135 patients. A region of interest was drawn within each lesion on DW images, avoiding any cystic/necrotic portion. Patient characteristics, classical histological prognostic factors (histologic type, grade, size, and lymph node (LN) status), molecular factors (ER, PR, and HER2) and genetic factors (BRCA, Oncotype DX scores) were reviewed and recorded. The relationships between ADC values and patient characteristics and prognostic factors were analyzed. Statistical analysis was performed using Student’s t-test and ANOVA (statistical significance was established at p= 0.05). ADC values are measured in units of 10-3 mm2/s.

The mean ADC value of the 148 malignant lesions was 1.00±0.170. The ADC values in lesions were not influenced by the BPE or breast density (respectively p=0.550 and p=0.967). The mean ADC values were significantly lower for the invasive ductal carcinoma (p=0.015), mass enhancement (p<0.001), BRCA positive lesions (p=0.032) compared to DCIS, invasive lobular carcinoma, non mass enhancement and BRCA negative lesions. The mean ADC values tended to be lower in premenopause women, high grade, LN positive, triple negative lesions (though not statistically significant). No statistical significant difference was observed in the ADC values among the different subgroups in size (<2cm, 2-5cm, >5cm), and molecular prognostic factors (ER positive, HER positive, TN). According to Oncotype Dx score (available for 27/41 ER positive tumors with negative LN) ADC values were higher in low risk (0.106±0.207) than in intermediate risk tumors (0.957±0.105), even if not statically significant different (p=0.100).

Our study shows that ADC may be a potential clinical adjunct in the evaluation of prognostic factors mostly in relation to the malignant lesion aggressiveness.

ADC may be a potential clinical adjunct in the evaluation of breast cancer prognostic factors.

Durando, M, Giri, D, Gnanasigamani, M, Deasy, J, Morris, E, Thakur, S, Measurement of ADC Values in Malignant Breast Lesions and their Relation to Classical and Molecular Prognostic Factors and Oncotype Dx.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14019337.html