Study suggests contrast-enhanced mammography as an alternative to breast MRI for imaging lobular carcinoma

The study found superior sensitivity of CEM compared to standard mammography; MRI and CEM overestimate tumour size similarly.

"Traditionally, breast MRI has been used in many centres for preoperative staging, but CEM appears to be a suitable alternative,” the researchers wrote.

Invasive lobular carcinoma is the second most histological breast cancer type after invasive ductal carcinoma. It accounts for 5% to 15% of the cases, but the previous reports suggest that there is a rise in the incidence of lobular carcinoma at a faster rate than other breast cancer subtypes.

It is also reported that mammography and ultrasound tend to underestimate lesion size in lobular carcinoma cases. Also, this type of breast cancer is less likely to be detected by mammography due to the growth pattern of infiltration and a density less than or equal to normal fibroglandular tissue. Considering this, breast MRI is recommended in preoperative workup in lobular carcinoma cases.

Previous studies have shown that the performance of CEM is comparable to breast MRI and could be helpful for patients with contraindications for MRI. Elisabetta Giannotti, Addenbrooke’s Cambridge University Hospital NHS Foundation Trust, Cambridge, UK, and colleagues aimed to assess the performance of contrast-enhanced mammography in the preoperative staging of invasive lobular carcinoma (ILC) of the breast. They also compared the results to standard mammography and MRI.

For this purpose, the researchers conducted a multicentre, multivendor multinational retrospective study of women with a histological diagnosis of ILC who underwent CEM from 2013 to 2021.

Multifocality and index lesion size was recorded for 2D mammography, CEM, and when available MRI. Comparison with histological data was done for the women treated by primary surgical excision.

115 ILC were included, 46 presented symptomatically, and 69 were screening detected. Based on the study, the researchers reported the following findings:

• CEM demonstrated superior sensitivity when compared to standard mammography.
• The correlation between the histological size measured on the surgical excision specimen size was higher than with standard mammography (r=0.626 and 0.295, respectively), with 19% of lobular carcinomas not visible without a contrast agent.
• The sensitivity of CEM for multifocal disease was greater than standard mammography (70% and 20%, respectively).
• CEM overestimated tumour size by an average of 1.5 times, with the size difference increasing for larger tumours.
• When MRI was performed (22), tumour size was also overestimated by an average of 1.3 times.
• The degree of size overestimation was similar for both modalities, with the tumour size on CEM being on average 0.5cm larger than on MRI.

"Contrast-enhanced mammography is a useful tool for the local staging of lobular carcinomas and could be an alternative to breast MRI," the researchers concluded.

Reference:

Giannotti, E., Van Nijnatten, T., Chen, Y., Bicchierai, G., Nori, J., De Benedetto, D., Lalji, U., Lee, A., & James, J. (2024). The role of contrast-enhanced mammography in the preoperative evaluation of invasive lobular carcinoma of the breast. Clinical Radiology. https://doi.org/10.1016/j.crad.2024.01.035