Ji Hyun Youk MD, Presenter: Nothing to Disclose

Eun Ju Son MD, PhD, Abstract Co-Author: Nothing to Disclose

Jeong-Ah Kim MD, PhD, Abstract Co-Author: Nothing to Disclose

To investigate factors influencing the evaluation of background parenchymal enhancement (BPE) at follow-up breast MR imaging after adjuvant endocrine therapy.

A total of 144 MR studies in 122 women with breast cancer and MR imaging findings of contralateral unaffected breast, before and after adjuvant endocrine therapy between January 2007 and March 2012 were retrospectively identified. Two readers working in consensus performed blinded side-by-side comparison of BPE before and after therapy. BPE was classified as the same or greater on one of the two MR studies and by using categorical scales: minimal, mild, moderate, or marked. The sign test was used to conduct a side-by-side comparison of BPE between two MR studies. Age, body mass index (BMI), menopausal status, the type of endocrine therapy (selective estrogen receptor modulator (SERM) or aromatase inhibitor (AI)), concomitant chemotherapy, follow-up duration from treatment to follow-up MR, BPE at baseline MR imaging before therapy, field strength of MR system used before and after therapy, and recurrence of breast cancer were analyzed for their association with BPE by using the χ2 test, independent t-test, and multivariate analysis.

A decrease in BPE occurred in 82.6% (119 of 144; SERM 89.6%, AI 68.8%) of women after therapy (P<0.01). Younger age (P<0.0001), lower BMI (P=0.001), premenopausal status (P<0.0001), difference in field strength of MR system (P=0.020), moderate/marked BPE at baseline MR imaging (P<0.0001), treatment with SERM (P<0.0001), no recurrence (P=0.003), and neoadjuvant chemotherapy (P=0.039) were significantly associated with the decrease of BPE after therapy. Multivariate logistic regression analysis showed that the difference in field strength of MR system and BPE at baseline MR imaging were significantly associated with the decrease of BPE after therapy.

The different field strength of MR system used before and after therapy and moderate/marked BPE at baseline MR imaging before therapy were associated with the decrease of BPE at follow-up breast MR imaging after adjuvant endocrine therapy.

When the change of BPE at follow-up MR imaging after adjuvant endocrine therapy is evaluated, the different field strength of MR system after therapy and BPE at baseline MR study should be considered.

Youk, J, Son, E, Kim, J, Follow-up Breast MR Imaging after Adjuvant Endocrine Therapy: Factors Influencing the Evaluation of Background Parenchymal Enhancement.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13016401.html