Surveillance MRI Study Shows Link Between Background Parenchymal Enhancement and Higher Risk of Second Breast Cancer

In a new retrospective study of over 2,600 women who underwent surgery for primary breast cancer, researchers found the risk of second breast cancer doubles for those who have background parenchymal enhancement (BPE) on surveillance magnetic resonance imaging (MRI).

The research, published earlier today in Radiology, involved 2,668 women who had surveillance MRI after receiving surgical treatment for primary breast cancer.¹ The mean age of the cohort at the initial MRI surveillance was 49 and they had no prior history of second breast cancer, according to the study. The study authors found that 109 women developed second breast cancer at a median follow-up of 5.8 years.

A multivariable assessment of the study findings revealed a 2.1 hazard ratio (HR) for the development of second breast cancer among women who had mild, moderate, or marked BPE on surveillance MRI in comparison to women with minimal BPE on MRI surveillance.¹

Other independent risk factors for the development of second breast cancer associated with mild, moderate, or marked BPE on surveillance MRI included being younger than 45 years of age at the time of the initial diagnosis of breast cancer (3.4 HR) and positive results from a BRCA 1/2 genetic test (6.5 HR), according to the study.¹

Emphasizing a lack of clarity on the mechanisms of the link between BPE and cancer risk, the study authors suggested that BPE may reflect the impact of hormonal stimulation on breast gland components as well as structural proliferative tissue changes. Adjunctive treatment for primary breast cancer may be another consideration with BPE according to the researchers.

“Surveillance breast MRI is usually performed after the completion of adjuvant treatment, including radiation therapy and/or chemotherapy or during endocrine therapy, which may alter the risk of second breast cancer. BPE at surveillance breast MRI may reflect the therapeutic response to adjuvant treatment and may be a predictor of the modified risk of second breast cancer after treatment in women with a PHBC (past history of breast cancer),” wrote Su Hyun Lee, M.D., Ph.D., who is affiliated with the Department of Radiology at Seoul National University Hospital in Korea, and colleagues. “In our study, mild, moderate, or marked BPE was associated with an increased risk of future second breast cancer in women with a PHBC, regardless of hormone receptor expression in initial breast cancer or endocrine therapy status.”

While the American College of Radiology (ACR) recommends annual surveillance MRI for those diagnosed with breast cancer prior to the age of 50 and women with dense breasts, the study authors suggested that BPE findings may enable clinicians to look at other surveillance options and help reduce exposure to gadolinium-based contrast agents.²

“Information obtained with BPE may help to better define the risk of second breast cancer and tailor imaging surveillance strategies,” noted Lee and colleagues. “For example, women with minimal BPE at surveillance breast MRI may no longer need to undergo contrast-enhanced breast MRI every year.”

Acknowledging the limitations of a retrospective study with data coming from one institution, the authors also noted they did not include varying breast densities and only included women who had been referred for MRI breast surveillance. Lee and colleagues also maintained that it was beyond the scope of this study to assess the impact of pre- and post-breast cancer treatment BPE changes on the risk of second breast cancer.

References

1. Lee SN, Jang MJ, Yoen H, et al. Background parenchymal enhancement at postoperative surveillance breast MRI: association with future second breast cancer risk. Radiology. 2022 Aug. 30. doi: 10.1148/radiol.220440. Online ahead of print.

2. Monticciolo DL, Newell MS, Moy L, Niell B, Monsees B, Sickles EA. Breast cancer screening in women at higher-than-average risk: recommendations from the ACR. J Am Coll Radiol. 2018;15(3 3 Pt A):408-414.