Impact of breast density in invasive lobular carcinoma

In this video, Josephine Van Cauwenberge, a resident in gynaecology and PhD researcher at the Laboratory for Translational Breast Cancer Research, presents research exploring the association between breast density, clinicopathological characteristics, and survival outcomes in patients with early-stage invasive lobular carcinoma (ILC). Breast density is routinely assessed on mammograms using the BI-RADS classification, ranging from least dense (A) to most dense (D), and is considered a marker of the breast tissue microenvironment.

ILC differs from invasive breast cancer of no special type at molecular, clinical, and histological levels, and this may be influenced by differences in the tumour microenvironment. For this reason, breast density represents an interesting factor to study in ILC. A large retrospective cohort of approximately 1,000 patients diagnosed with pure ILC between 2000 and 2020 at University Hospitals Leuven was evaluated. Mammograms were available for 566 patients and were independently reviewed by five radiologists, with breast density scores assigned using a majority vote approach to improve consistency.

Higher breast density was associated with younger age, lower rates of overweight and obesity, and a trend towards lower tumour grade. In addition, high breast density at diagnosis was associated with better disease-free survival and overall survival, both in univariable and multivariable analyses.

These findings highlight breast density as a potentially relevant prognostic factor in ILC and reinforce the need for further research to clarify the biological mechanisms behind these associations.