Even though dense breast tissue is a risk factor for breast cancer, very low mammographic breast density is associated with a worse prognosis in breast cancer patients.
Patient survival is affected only when low breast density is combined with an abundance of hyaluronan in the tumor, shows recent research from the University of Eastern Finland and Kuopio University Hospital.
Breast cancer is the most common cancer in women and the leading cause of women’s cancer deaths.
The main established prognostic factors are tumor size and differentiation grade, spreading to armpit lymph nodes, hormone receptor status and HER2-positivity.
However, there’s a need to define new and more accurate prognostic factors that could also allow for more personalized treatments.
Mammographic breast density (MBD) has been a topic of research and discussion for decades.
However, the focus has been mostly on the effect of MBD on screening sensitivity, masking effect and its status as a risk factor for breast cancer formation.
Women with very dense breast tissue are known to have a 4- to 6-fold risk of breast cancer.
The study concentrated on a less widely studied aspect of MBD — its prognostic effect in women who already have breast cancer.
In a study involving 278 breast cancer patients, researchers examined the prognostic value of MBD and mammographic tumor features and their relationship with the established prognostic factors.
Very low MBD was found to be an independent prognostic factor for breast cancer. It was also associated with higher tumor grades and predicted worse survival.
Hyaluronan (HA) is a molecule naturally present in nearly all tissue types, but in cancer the metabolism of HA may change and promote the progression of cancer.
In the study, a strong link was found between low breast density and high expressions of HA.
Moreover, there was a dramatic reduction in patient survival exclusively when HA abundance was combined with low breast density.
According to the leading author, the findings suggest that dense breast tissue carries a more favorable prognosis and the mechanisms of cancer development are different from those of progression and aggressiveness.
News source: University of Eastern Finland.
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