Factors Influencing the Background Parenchymal Enhancement in Follow-Up Breast MRI after Adjuvant Endocrine Therapy

ABSTRACT

PURPOSE: To investigate factors influencing the evaluation of background parenchymal enhancement (BPE) at follow-up breast magnetic resonance imaging (MRI) after adjuvant endocrine therapy. MATERIALS AND METHODS: One hundred twelve women with breast cancer and MRI of the contralateral unaffected breast before and after endocrine therapy were identified. Two readers in consensus performed blinded side-by-side comparison of BPE (minimal, mild, moderate, and marked) before and after therapy with categorical scales. Age, body mass index, menopausal status, treatment regimen (selective estrogen receptor modulator or aromatase inhibitor), chemotherapy, follow-up duration, BPE at baseline MRI, MRI field strength before and after therapy, and recurrence were analyzed for their influences on decreased BPE. RESULTS: Younger age, premenopausal status, treatment with selective estrogen receptor modulator, MRI field strength, and moderate or marked baseline BPE were significantly associated with decreased BPE. In multivariate analysis, MRI field strength and baseline BPE showed a significant association. CONCLUSION: MRI field strength and baseline BPE before and after therapy were associated with decreased BPE at post-therapy, follow-up MRI.