Sana Parsian MD, Presenter: Nothing to Disclose

Brenda Kurland PhD, Abstract Co-Author: Nothing to Disclose

Ryan Sun BS, Abstract Co-Author: Nothing to Disclose

Habib Rahbar MD, Abstract Co-Author: Nothing to Disclose

Constance D. Lehman MD,PhD, Abstract Co-Author: Research Consultant, Bayer AG Research Consultant, General Electric Company Research Consultant, Koninklijke Philips Electronics NV

Savannah Corrina Partridge PhD, Abstract Co-Author: Research grant, Koninklijke Philips Electronics NV

Early assessment of response to neoadjuvant chemotherapy (NAC) for patients with locally advanced breast cancer (LABC) is imperative for timely optimization of therapy protocols and to spare nonresponders unnecessary toxicities. We investigated the utility of quantitative diffusion weighted (DW) and dynamic contrast-enhanced (DCE) MRI features to predict pathologic complete response (pCR) in patients with LABC by mid-NAC.  

After IRB approval, we retrospectively reviewed 21 consecutive patients with LABC (from 1/2006 to 5/2009) who underwent breast MRI (DCE and DW) at three time points: pre-NAC (n=21), mid-NAC (within first 12 weeks of treatment, n=15/21) and post-NAC (n=18/21). All patients received the same regimen of weekly doxorubicin/daily cyclophosphamide for 12 weeks followed by paclitaxel (plus trastuzumab for HER2+ tumors). MRI measurements at each time point included longest diameter (LD), tumor volume (TV), initial peak enhancement (PE) and apparent diffusion coefficient (ADC). Mid-NAC percent changes in MRI parameters were compared in patients with and without complete pathologic response (pCR) by Wilcoxon signed rank test and Mann-Whitney U test. Multivariate logistic regression analysis was used to find significant independent predictors for pCR.  

Mean pre-NAC lesion size was 59.1±27.4 mm. All MRI parameters changed significantly (p<0.05) from pre to mid-NAC and from pre to post-NAC. Eleven of 21 patients demonstrated pCR at the time of surgery. At mid-NAC, changes in peak PE and minimum ADC were significantly predictive of pCR (p=0.029, p=0.016, respectively), and change in TV was marginally predictive (p=0.052). Mid-NAC change in LD was not significantly different between pCR and non-pCR groups (p=0.2). In multivariate analysis, change in ADC min by mid-NAC was the only independent significant predictor of pCR (AUC=0.89, p=0.003).  

Both DCE and DW MRI reflected response mid-treatment, and minimum ADC was the most predictive marker of pathologic response. These results suggest quantitative MRI biomarkers could provide early indication of treatment efficacy in patients undergoing NAC, warranting further study in larger cohorts.  

Incorporating quantitative measures into clinical breast MRI protocols may potentially improve treatment response assessment in breast cancer patients undergoing NAC.  

Parsian, S, Kurland, B, Sun, R, Rahbar, H, Lehman, C, Partridge, S, Quantitative MRI Biomarkers Predict Pathologic Response in Neoadjuvant Chemotherapy Treatment of Breast Cancer.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12033616.html