Breast density can influence cancer recurrence, study finds

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It’s becoming increasingly clear that women should learn, as part of an overall risk-assessment for breast cancer, whether they have dense breast tissue. Not only is it harder to detect a tumor in dense breast tissue, studies show that the risk of breast cancer is increased up to six times in women with the highest breast density scores compared with women with the lowest breast density scores.

Now a study suggests breast density may play a role in determining the best treatment strategy for women diagnosed with breast cancer. Researchers at the Women’s College Research Institute in Toronto evaluated the medical records of 335 women who had undergone a lumpectomy for breast cancer. The researchers assessed the breast density of the women, as seen on their mammograms, and monitored them for a recurrence of cancer.

The study found that patients with the highest breast density had a much higher risk of cancer recurrence than did women with the lowest breast density. After 10 years, the women with the highest breast density had a 21% chance of recurrence compared with 5% among the women with the lowest density. Among women who did not receive radiation therapy after the lumpectomy, those with high-density breast tissue had a 40% chance of recurrence.

It may be important for women who undergo lumpectomy to have additional cancer therapies if they have high-density breast tissue, the authors concluded, even though it’s a mystery as to why dense tissue is more problematic.

‘The biological basis for the associations between mammographic density, breast cancer risk and breast cancer recurrence are not known,’ they wrote.

The study is published online in the journal Cancer.

-- Shari Roan