Abstract P4-02-08: MRI changes in breast skin following preoperative therapy for inflammatory breast cancer (IBC)

Abstract

Abstract Purpose: Standard treatment for IBC includes preoperative systemic therapy (PST), followed by mastectomy (M) and adjuvant radiation (R). Determining the optimal sequencing of M and R after PST may be difficult when clinical changes suggest residual disease within breast skin. With the goal of selecting appropriate patients (pts) for M prior to R, we correlated pathologic disease response in breast skin with changes in skin thickness and enhancement determined by MRI. Methods: An IRB approved database of IBC pts evaluated at Dana Farber Cancer Institute (DFCI) from 1997-2013 was used for retrospective analysis. 40 pts met criteria: confirmed diagnosis of IBC, completed PST followed by M without preoperative R. Baseline and post-PST breast MRI imaging was reviewed. Using the ACR BI-RADS lexicon, we recorded skin thickness, qualitative enhancement and kinetic analysis using computer-aided detection post-processing software. Findings were correlated with pathologic response in skin found at M. Results: MRI showed baseline skin thickening in all 40 pts (median 6mm, range 3-13mm). Although 34 (85%) had persistent skin thickening post-PST (median 4 mm, range <3-13 mm), there was a significant overall reduction in skin thickness (p<0.001); median decrease =2mm, range 1-7mm. MRI showed qualitative skin enhancement at baseline in 39/40 pts. 29 (73%) had medium/fast initial phase kinetics: 25 persistent delayed phase kinetics, 2 wash-out, 2 plateau. 20 pts had residual qualitative skin enhancement post-PST; 11 pts (28%) had medium/fast initial phase kinetics, all persistent delayed kinetics. The decrease in skin thickness was significantly greater among the 19 pts achieving resolution of skin enhancement post-PST compared with the decrease in skin thickness among the 20 pts with residual skin enhancement (p=0.02). 8 pts (20%) had residual tumor within the skin at M. All 8 pts had thicker skin on post-PST MRI (median 5 mm, range 3-13mm) compared with pts without residual disease in the skin (median 3.5mm, range <3-11 mm). Qualitative skin enhancement post-PST was seen in 63% of pts (5/8) with residual skin disease compared with 47% of pts (15/32) without disease. Conclusion: Although IBC pts have skin thickening demonstrated by MRI at baseline, there is a statistically significant reduction in the skin thickness following successful PST. This correlates with a reduction in enhancement of the skin shown by MRI imaging. More substantial and persistent skin thickening with enhancement was seen in the setting of residual dermal lymphatic involvement following the completion of PST, though this study is too small to detect any significant correlation. Since an accurate assessment of residual disease in breast skin is vital in determining the optimal sequencing of M and R following PST in IBC pts, MRI evaluation of skin thickness and enhancement may be a useful tool to predict residual disease and guide surgical management of IBC. Citation Format: Yeh E, Rives A, Guo H, Regan M, Birdwell R, Nakhlis F, Bellon J, Warren L, Hirshfield-Bartek J, Jacene H, Dominici L, Overmoyer B. MRI changes in breast skin following preoperative therapy for inflammatory breast cancer (IBC). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-02-08.