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?

Abstract

Purpose: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 Sidak post hoc tests were conducted for multiple comparisons. Paired t-tests were conducted to examine changes over time, and two-tailed P values 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.Conclusion: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.

Evaluation of the effects of neoadjuvant chemotherapy on probably benign breast lesions with MRI: Report of two cases

“…It can be considered that benign lesions undergo the same process as malignant lesions during treatment and after the NAC they show a decrease in size and decrease in enhancement in MRI. With similar changes, we can see the loss of contrast enhancement in benign lesions in MRI (7). Our benign lesions were considerably smaller than cancer lesions and our data was limited.…”

“…Pathology results were fibroadenoma when they were excised. NAC reduces vascular support by affecting the endothelial layer of vessels (7). Yeh et al and Moll et al showed increased fibrosis in normal glandular tissue, decreased cellularity and, histological changes such as lobular atrophy after the neoadjuvant chemotherapy (6,10).…”

“…In cases with breast cancer, the next approach depends not only on the size of known cancer, but also on the presence of additional lesions that may be on the same or the other breast (7). The most valuable diagnostic tool in evaluating the distribution of the malignant lesion, detecting additional lesions, and evaluating NAC response is MRI (8).…”