Beware! Dense breasts doubles risk of cancer: Study

Beware! A study finds that women with dense breasts have two-fold increased risk of developing breast cancer.

The study, published in the journal Cancer, is among the first to find the association between breast density (BD) and contralateral breast cancer (CBC).

According to experts, dense tissue makes tumours harder to spot on mammograms - and that women should seek other screening alternatives.

"We know there are a number of well-established influences for developing both primary and secondary breast cancers, such as BRCA mutations, family history, and the tumor's estrogen receptor status," explained Bedrosian from Breast Surgical Oncology.

"We also know density is a risk factor for the development of primary breast cancer. However, no one has closely looked at it as a risk factor for developing contralateral disease," Bedrosianadded.

Each woman was placed into four categories of breast density: almost entirely fat, mostly fat, moderately dense and predominantly dense.

Of the selected patients, 229 were cases and 451 were controls.

The MD Anderson researchers categorised each patient's breast density by mammogram reading, assessed at the time of first diagnosis, as "nondense" or "dense," using the categorisations from the American College of Radiology.

Among the cases, 39.3 percent were classified as having nondense breast tissue and 60.7 percent as having dense breast tissue, compared to 48.3 percent and 51.7 percent, respectively, in the controls.

After adjusting for known breast cancer risk factors, the researchers found almost a two-fold increased risk of developing CBC in breast cancer survivors with dense breasts.

Breast tissue is composed of milk ducts and glands, dense breast tissue and fatty tissue - sometimes referred to as non-dense.

In the long-term, the researchers hope to use this tool to counsel patients on their personal risk and their options for treatment and surveillance, if their risk is sufficiently high.