Effects of Neoadjuvant Chemotherapy on Benign Breast Lesions Compared to Cancers: Should an Additional Lesion on Magnetic Resonance Imaging Responding Similar to Cancer after Neoadjuvant Chemotherapy be Viewed with Suspicion?
OBJECTIVE
Determining the effects of neoadjuvant chemotherapy (NAC) on benign breast lesions and to evaluate their response in comparison to breast cancers.


METHODS
A retrospective analysis performed on breast cancer patients between 2008 and 2014 to identify patients who had a pre- and post-NAC magnetic resonance imaging (MRI) and biopsy-proven benign lesions. Pre- and post-NAC size and intensity of enhancement of benign lesions and cancers were measured. Breast glandularity and background enhancement were graded. A 2 × 2 repeated measures ANOVAs and Sidakpost hoctests were conducted for multiple comparisons. Pairedt-tests were conducted to examine changes over time, and two-tailedPvalues were reported.


RESULTS
The effects of NAC in 38 cancers were compared to the effects of NAC in 47 benign lesions in these patients. From pre- to post-NAC, the mean size (cm) of malignant lesions on MRI decreased from 4.09 (±standard deviation [SD] 2.51) to 1.54 (±SD 2.32), (P< 0.001); the mean size (cm) of benign lesions decreased from 0.83 (±SD 0.54 cm) to 0.28 (±SD 0.51), (P< 0.001). Both benign and malignant lesions decreased in size after NAC, the size reduction in malignant lesions was significantly greater than benign lesions. From pre- to post-NAC, the mean lesion enhancement of the malignant lesions (scale 1-4) decreased from 3.43 (±SD 0.80) to 1.02 (±SD 1.34); the mean lesion enhancement of benign lesions decreased from 2.96 (±SD 1.04) to 0.98 (±SD 1.51). For both benign and malignant lesions, there was a significant overall reduction in enhancement after NAC from moderate at pre-NAC to minimal at post-NAC,P< 0.001. There was no overall difference in the enhancement of cancers (mean = 2.22, SD = 0.79) versus benign lesions (mean = 1.97, SD = 1.08), (P= 0.23). There was no significant change in glandularity from pretherapy (mean = 3.11, SD = 0.84) to posttherapy (mean = 3.13, SD = 0.82),P< 0.001.


CONCLUSIONS
Similar to cancers, benign breast lesions also show a significant decrease in size and enhancement after NAC; however, the decrease in size is less compared to cancers.
Department of Radiology, Medical University of South Carolina, Charleston, SC 29425, USA.
Rebecca
R
Leddy
Department of Radiology, Medical University of South Carolina, Charleston, SC 29425, USA.
Abid
A
Irshad
Department of Radiology, Medical University of South Carolina, Charleston, SC 29425, USA.
Lara
L
Hewett
Department of Radiology, Medical University of South Carolina, Charleston, SC 29425, USA.
Heather
H
Collins
Department of Radiology, Medical University of South Carolina, Charleston, SC 29425, USA.
Frank
F
Vento
Department of Radiology, Medical University of South Carolina, Charleston, SC 29425, USA.
Susan
S
Ackerman
Department of Radiology, Medical University of South Carolina, Charleston, SC 29425, USA.
Madelene
M
Lewis
Benign breast lesions on magnetic resonance imaging; breast cancer; breast magnetic resonance imaging; neoadjuvant chemotherapy