Fibroglandular tissue and background parenchymal enhancement on breast MRI following bilateral-salpingo-oophorectomy

It has been well-studied that women with a BRCA1 or BRCA2 gene mutation have an increased risk for breast and ovarian cancer. One of the recommended interventions is a bilateral salpingo-oophorectomy (BSO), which decreases a BRCA1 or BRCA2 mutation carrier’s risk of developing ovarian and breast cancer. Since ovaries produce natural hormones, which also stimulate breast cells, removal of ovaries and thus, removal of natural hormones, could decrease breast cancer risk. Two biomarkers, background parenchymal enhancement (BPE) and fibroglandular tissue (FGT), are reported on breast MRI images. Each has been studied as a qualitative way to determine a woman’s residual breast cancer risk post-BSO. It is hypothesized that since BPE and FGT are influenced by hormones, a decrease in BPE and FGT could be interpreted as a decrease in breast cancer risk. To further investigate this phenomenon, we performed a retrospective study, reviewing medical records and collecting data of patients all from the University of California, San Francisco (UCSF) Cancer Center. BPE, FGT and breast density categories will be collected pre- and post- BSO. We plan to see a decrease in BPE, FGT and breast density post-BSO. In total, thirteen patients were identified that fit our inclusion criteria. Seven patients were analyzed in our study population for BPE. Analyzing BPE, the Wilcoxon Signed-Rank Test analysis did not find a significant decrease in BPE post-BSO (Z=-0.276, p=0.783). Thirteen patients were identified that fit our population inclusion criteria for FGT. The Wilcoxon Signed-Rank Test analysis did not find a significant decrease in FGT post-BSO (Z=-1.000, p=0.317). A secondary analysis was conducted to assess whether breast density decreased post-BSO. We used the same inclusion criteria as BPE and FGT and obtained 19 women, 9 of which were previously analyzed for BPE and FGT. The results of the Wilcoxon Signed-Rank Test did not find significant results (Z=0.378, p=0.705). Additional studies are required before we are able to obtain enough evidence to incorporate BPE and FGT biomarkers as a qualitative approach to determining residual cancer risk post-BSO.