Women with 'dense' breasts who have been treated for breast cancer are significantly more likely to see the condition return, scientists have claimed.
Scientists working at the Women's College Hospital in Toronto looked into the records of 335 women who were treated for invasive cancer, with their breasts categorised as being of low, intermediate or high density.
They found that, even after having benefited from surgery, those with high density breasts were four times more likely to suffer a relapse than those at the other end of the scale, suggesting that they should be given extra radiation therapy.
Furthermore, this trend was found to increase over time, with 40 per cent of high-density breasted women suffering a recurrence of cancer ten years after initial diagnosis.
Commenting on his team's findings, study leader Dr Stephen Norad noted that the composition of breast tissue could be used as a key indicator as to whether or not cancer is likely to return after surgery, though he added that 'breast density has been found to be modifiable to some extent by physical activity and hormone therapy'.
Just recently, the Fox Chase Cancer Center in the US reported that one in three breast cancers changes as it spreads, with this likely to explain why some women do not respond to some treatments.