Ultrasound plus Mammography, Good combo for breast cancer detection

A recent study has shown that ultrasound combined with mammography increases the chances of breast cancer detection and also gives more accurate results.

Mammography is the process of using low-dose X-rays (usually around 0.7 mSv) to examine the human breast. It is used to look for different types of tumors and cysts.

Breast cancer is the second leading cause of cancer death in women, first being the lung cancer. According to the American Cancer Society, more than 180,000 American women are diagnosed with breast cancer every year and almost 41,000 die because of it.

“Mammograms saw only half of the breast cancers that were present,” said Dr. Wendie Berg of American Radiology Services at Johns Hopkins at Green Spring Station in Lutherville, Md., who was also study’s lead author. “If we added ultrasound to mammography, we saw 78 percent of the cancers.”

Dr. Berg and her colleagues studied around 3000 women from April 2004 to February 2006 in which the subjects underwent either a mammogram alone or a mammogram and ultrasound. They all had an average age of 55-years old and had a higher-than normal risk of breast cancer.

They were split up into groups randomly to get either a mammogram, or a mammogram with an ultrasound.

Researchers found that the mammogram on its own detected 7.6 cases of cancer per 1,000 women, while 11.8 cases per 1,000 women were detected in the group that had the mammogram and ultrasound.

Dr. Berg said that most of the cancers found with ultrasound were small invasive cancers that had not spread to the lymph nodes. “These are types of cancers that we most need to be finding,” she said.

But the new technique also has a few disadvantages. There's a significant chance of false positives with ultrasounds, which could lead to unnecessary biospies. And radiologists say the time and expertise needed to analyze an ultrasound make it an unrealistic choice for many patients.

The time it takes to analyze an ultrasound exam, compared to an MRI or a mammogram, is another drawback, said Dr. David Ecanow, co-chief of the section of breast imaging for Evanston Northwestern Healthcare. It also hasn't proved to be more effective than magnetic-resonance imaging in women at high risk for breast cancer.

Last year, the American Cancer Society recommended MRIs, in addition to mammograms, for women who have an estimated lifetime risk of breast cancer of at least 20 percent.

Berg agrees with the recommendation, but for some women, ultrasound screening might be a reasonable alternative to MRI, if MRI is unavailable or too expensive, she said.