Ultrasound Cancer Screen More Effective for Many Women

By Bob Dart

Ultrasound screening can detect cancers that mammograms miss in women with dense breasts, according to a five-year study released Thursday.

``While mammography detected 98 percent of cancers in women with fatty breasts, it found only 48 percent in women with the densest breasts,'' said Dr. Thomas M. Kolb, a New York City radiologist and co-author of the study, which will appear in the October issue of the journal Radiology.

Additional screening by ultrasound increased the number of women diagnosed with cancers by 42 percent, according to the study of 27,825 consecutive screening sessions performed on 11,130 women who had no signs of breast cancer when they enrolled.

Over the course of the study, which lasted from 1995 to 2000, 246 cancers were diagnosed in 221 women.

The key result: ``Screening ultrasound finds tumors that mammography misses,'' said Kolb.

``Women with dense breasts, and especially those that are high-risk, would strongly consider having a screening ultrasound as well,'' Kolb said at an American Medical Association conference for science reporters.

A mammogram, which is an X-ray of the breast, shows fat as black and glandular or dense tissue as white. Cancer masses also show up as white. Therefore, a mammogram shows a white cancer mass in stark contrast on a predominately black fatty breast, but a small white spot that may be cancerous can go undetected on the white mammogram of a dense breast.

Ultrasound screening depicts most cancers as black spots - much easier to see against the white of dense breast tissue.

``It is important for women with dense breasts to have a mammogram before proceeding to ultrasound,'' said Kolb. ``It is the combination of mammography plus ultrasound that is most effective.''

``As far as how effective a mammogram is for a particular woman, it is more important for that woman to know her breast density than her age,'' he said.

Many women do not know if they have dense breasts. The only way to determine breast density is with a mammogram, and not by a breast's appearance or a physical examination, said Kolb.

Kolb recommended that women ask their doctors whether they have dense or fatty breasts. Those with dense breasts who want supplemental screening sonograms should find an experienced physician, preferably one who performs the procedure at least five times a day, said Kolb.

A screening ultrasound takes from four to 20 minutes to perform and costs from $100 to $150, said Kolb. Insurance companies rarely pay for the procedure because this is not an accepted technique.

In the study, 49 percent of the women were classified as having dense breasts.

Younger women are more likely to have dense breasts than are older ones. However, women taking hormone replacement therapy are more likely to have dense breasts than comparably aged women who don't.

Researchers in Canada, Australia and New Zealand studying identical and fraternal twins found that variations in breast density were strongly influenced by genetic factors, according to a study in Thursday's New England Journal of Medicine cited in the New York Times.