Role of ultrasound of the breasts in screening Mammography is NOT perfect and picks up on average 85% of the breast cancers. As the density of the breast increases, the cancer pick up rate for mammograms decreases. Some small cancers hidden in dense breasts can go unnoticed on mammograms. Women with denser breasts generally have a higher proportion of milk-producing glands relative to fatty tissue inside the breast. Some older postmenopausal women undergoing hormone replacement therapy also develop dense breasts. This glandular density is unrelated to size, shape, texture or lumpiness of the breasts. Women who do not have much fatty tissue in their breasts can benefit from ultrasound screening examinations in addition to routine mammogram. It has been used as a standard adjunct to mammography in many centres. Newer techniques, high frequency and sophisticated, more expensive ultrasound machines have been reported to be able to pick up some of the smaller tumours and even unusual calcifications in screening breast ultrasounds. Current evidence does not recommend ultrasound alone as a reliable screening tool for breast cancer. It lacks fine detail, cannot detect most calcium deposits, is largely dependent on the operator (the radiologist or ultrasound technologist, also known as the sonographer), and cannot document how much breast tissue has been imaged and also has its share of false pick-ups or missed cancers. Mammography continues to be the most important screening tool for breast cancer and combining the mammography with ultrasound may prove to be an important way to increase sensitivity in women with dense breast tissue. Studies looking at all the risks and benefits of screening with high-resolution ultrasound and mammography, including costs and long-term effects on survival are ongoing. In the meantime, it is too early to promote widespread ultrasound screening for women, even for those with dense breasts. | 
