Women with dense breasts who had breast cancer are at a higher risk of having a recurrence after lumpectomy than other women, according to a new study.

The results may mean that breast cancer patients with dense breasts may benefit from additional therapies such as radiation, according to a news release on the work.

Earlier studies found that women with dense breast tissue are also at increased risk of having breast cancer.

Researchers from the Women's College Research Institute reviewed the records of 335 women who had a lumpectomy and made three groups based on breast tissue density.

Those with the highest density had a 21 percent chance of recurrence over 10 years. Women in the lowest category had a 5 percent chance.

"The composition of the breast tissue surrounding the breast cancer is important in predicting whether or not a breast cancer will return after surgery," said Dr. Steven A. Narod.

The work appears in the Dec. 15, 2009, issue of Cancer.