Toronto, May 14 (IANS) A new study has found that mammography and ultrasound can play complementary roles in detecting breast cancer in high-risk women. Canadian and American researchers have found that each technique detects cancers that the other cannot. The study confirms that the detection rate of breast cancer is much higher when both ultrasound and mammography are used.

In their study on 2,600 high-risk women, the researchers diagnosed them with mammography, ultrasound and then with a combination of mammography and ultrasound. When they compared the results, they found that with mammography the detection rate was 78 per cent. With ultrasound, it was 80 per cent.

But with both mammography and ultrasound, it went up to 91 per cent.

The study also found that mammography alone detected 7.6 cancers per 1,000 high-risk women. But when it was combined with ultrasound, 11.8 cancers were detected per 1,000 high-risk women.

The researchers also found that despite its comparatively higher cancer detection rate, ultrasound also showed false-positive rate of 8.1 per cent. For mammography, this rate was just 4.4 per cent.

The study, published in the Journal of the American medical Association, also found that mammography was more effective in cancer detection in women with fatty breast tissue than those with dense breast tissue.

The study also showed that ultrasound picked up cancers which were very small and at very early stages of development.

Breast cancer kills more than 5,000 women in Canada each year.