Hee Jung Shin MD, Presenter: Nothing to Disclose

Nola Michiko Hylton PhD, Abstract Co-Author: Nothing to Disclose

Lisa Wilmes PhD, Abstract Co-Author: Nothing to Disclose

David Newitt PhD, Abstract Co-Author: Nothing to Disclose

Ella Fung Jones PhD, Abstract Co-Author: Nothing to Disclose

Rebekah McLaughlin, Abstract Co-Author: Nothing to Disclose

To investigate tumor apparent diffusion coefficient (ADC) and fractional anisotropy (FA) measured by diffusion tensor imaging (DTI) as predictors of pathologic complete response (pCR) in patients with locally advanced breast cancer (LABC) after neoadjuvant chemotherapy (NAC).

In this HIPAA-compliant institutional review board-approved study, forty patients with LABC (mean tumor size, 4.0 cm; range, 0.6—9.9 cm) were enrolled between September 2010 and November 2012. MR imaging including DTI was performed on a 1.5T scanner before NAC (MR1) and after one cycle of taxane-based treatment (MR2). ADC and FA prior to treatment and after one cycle of NAC were measured from DTI data. Pretreatment values (MR1), early treatment values (MR2), and early percent change of these variables (between MR1 and MR2) were compared between pCR and non-pCR groups using the Mann-Whitney U test. Receiver operating characteristic (ROC) curve analysis was performed to assess the diagnostic performance of each parameter and the area under the ROC curve (AUC) was compared.

After one cycle of treatment, 9 patients (22.5%) showed pCR and 31 patients (77.5%) showed non-pCR. Prior to pretreatment, only tumor ADC showed a statistically significant difference between pCR and non-pCR groups (1.07 ± 0.20 X 10-3 vs. 1.12 ± 0.10 X 10-3 mm2/sec, respectively) (P=0.029). After one cycle of treatment, patients with pCR had statistically significantly higher percent changes of tumor ADC (P<0.001) and FA (P=0.008) than those with non-pCR. In the ROC analysis, tumor ADC and FA had AUCs of 0.74 and 0.56 at pretreatment and 0.65 and 0.58 at early post-treatment. AUCs for early change in ADC and FA were 0.89 and 0.79, respectively.

Patients with pCR showed significantly lower pretreatment ADCs than those with non-pCR. Early percent change in both ADC and FA was associated with pCR. These results suggest that both diffusion related parameters provide information that can be used for early assessment of response to NAC in patients with LABC.

The prediction of pCR using DTI-based quantitative measurements of fractional anisotropy could help determine surgical planning and predict long-term outcome.

Shin, H, Hylton, N, Wilmes, L, Newitt, D, Jones, E, McLaughlin, R, Diffusion Tensor Imaging for Prediction of Pathologic Response to Neoadjuvant Chemotherapy in Patients with Breast Cancer.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13044158.html