Contrast-Enhanced Mammography Study Examines Impact of Clinical Factors on Background Parenchymal Enhancement

The degree of background parenchymal enhancement (BPE) on contrast-enhanced mammography (CEM) is reportedly lowest during days eight through 14 of the menstrual cycle of premenopausal women with regular cycles.

This is one of the findings from a new retrospective study looking at the impact of clinical factors upon early BPE on CEM. For the study, recently published in the American Journal of Roentgenology, researchers reviewed clinical data from the electronic medical records (EMRs) and imaging of 207 women (median age of 46) who had contrast-enhanced mammography exams between April 2020 and September 2021.¹

According to the study, the researchers used two different criteria to assess the degree of BPE with “criteria 1” involving dual-energy subtraction (DES) imaging of a standard craniocaudal image of the suspicious or affected breast, and “criteria 2” involving the greater degree of BPE on DES imaging of craniocaudal views of both breasts.

For both criteria, the study authors found a lower degree of BPE for older patients, those with a personal history of breast cancer and patients with a history of chemotherapy or radiation therapy. Patients with dense breasts had a higher degree of BPE, according to the researchers. The researchers also pointed out that postmenopausal and perimenopausal status had negative associations with BPE degree whereas premenopausal women with regular or irregular menstrual cycles had positive associations with BPE degree.¹

In the multivariable analysis, the study authors noted that menstrual status and timing of menstrual cycle were the only independent predictors of BPE degree. For premenopausal women with regular menstrual cycles, the researchers found the lowest degree of BPE occurred during days eight through 14 of the menstrual cycle.

“This finding may reflect fluctuation in circulating estrogen levels throughout the menstrual cycle and the effects of estrogen on vascularization. This association could inform decisions regarding scheduling of CEM examinations based on the time of the menstrual cycle,” wrote study co-author Yajia Gu, M.D., who is affiliated with the Department of Radiology at the Fudan University Shanghai Cancer Center in China, and colleagues.

(Editor's note: For related content, see "Study Highlights Use of Contrast-Enhanced Mammography in Women with Breast Implants," "Key Considerations with Implementing Contrast-Enhanced Mammography in Your Practice" and "Current Insights on Breast Density, Contrast-Enhanced Mammography and Supplemental Breast Cancer Screening.")

In regard to univariable analysis associations of younger age, dense breasts and premenopausal status that were linked to a higher degree of BPE in the study, Gu and colleagues said “ … these associations may represent decreases in estrogen hormone levels and in fibroglandular tissue as patients age.” However, noting the work of other authors who found no difference with BPE degree with respect to age in premenopausal and postmenopausal women, Gu and colleagues suggested that “ … menstrual status, which reflects hormonal status, may have a more direct influence on BPE than does age.”^2,3

Acknowledging the limitations of a retrospective study with a small sample size, the study authors also conceded patient selection bias with high proportions of women with newly diagnosed breast cancer as well as women with dense breasts in the study cohort. However, Gu and colleagues noted the focus of the study was on CEM, which was not employed for screening purposes during the study. The researchers noted they did not assess the relationship between BPE degree and additional risk factors for breast cancer, nor did they evaluate whether higher BPE affected cancer detection rates.

References

1. Wang S, Sun Y, You C, et al. Association of clinical factors and degree of early background parenchymal enhancement on contrast-enhanced mammography. AJR Am J Roentgenol. 2023 Jan 25. Doi: 10.2214/AJR.22.28769. Online ahead of print.

2. King V, Goldfarb SB, Brooks JD, et al. Effect of aromatase inhibitors on background parenchymal enhancement and amount of fibroglandular tissue at breast MR imaging. Radiology. 2012;264(3):670-678.

3. Zhao S, Zhang X, Zhong H, et al. Background parenchymal enhancement on contrast-enhanced spectral mammography: influence of age, breast density, menstruation status, and menstrual cycle timing. Sci Rep. 2020;10(1):8608.