Ultrasounds Improve Breast Cancer Detection Rates

A study involving more than 70,000 women in Japan has shown that performing an ultrasound on top of the standard mammogram increases the sensitivity of breast cancer detection.

AsianScientist (Nov. 13, 2015) – Adding ultrasound to standard mammography tests in breast cancer screening can improve the rates of detection for breast cancer in women, according to a new study published in The Lancet.

Researchers led by Professor Noriaki Ohuchi, from Tohoku University Graduate School of Medicine, in Miyagi, Japan, recruited more than 70,000 women in Japan aged between 40 and 49 to participate in the Japan Strategic Anti-cancer Randomized Trial (J-START) trial. Half were offered the usual mammography screening, and half were offered ultrasound testing in addition to mammography, with two screening sessions taking place over two years.

The results show that ultrasound combined with mammography resulted in correct identifications of cancer in more than nine out of ten cases (91 percent sensitivity), whereas for women given mammography alone, just over three quarters of tests correctly identified breast cancer (77 percent sensitivity).

Breast cancer affects large numbers of women in Europe and the US, but rates are increasing rapidly in Japan and other Asian countries. Early detection and treatment is critically important for reducing deaths from the disease, and many developed countries have implemented mammography screening programmes for the women who are at risk.

Breast cancer tends to present earlier in Asian women compared to European or American women. Asian women have denser breast tissue. These two factors reduce the accuracy of mammography. As such, detection using standard mammography screening based on European and US practices might miss cases of breast cancer in Asian countries.

In addition to increased the accuracy of breast cancer detection, adding ultrasound to mammography detected more cancers at an early stage (144 cancers at stage 0 or 1, compared to 79 cancers at stage 0 or 1 detected by mammography alone). The addition of ultrasound also resulted in fewer interval cancers, which appear after a negative test result between scheduled rounds of screening. Researchers conclude that adding ultrasound to mammography screening allowed early detection of breast cancer, compared to mammography alone.

While previous studies have suggested that the addition of ultrasound might lead to an excessively high rate of ‘false positive’ results (where screening results falsely indicate that a cancer is present), these results suggest that the difference in false positive rates between the two testing protocols was small, and could be further reduced by ensuring that mammography and ultrasound test results are analyzed together.

“Our results suggest that adding ultrasound to mammography results in more accurate screening results for women in Japan, which could ultimately lead to improved treatment and reduced deaths from the disease,” said Ohuchi.

“Further work will now be needed to see if these results can be extended to other countries in Asia. In addition, long-term follow-up of these results will determine whether including ultrasound tests in breast cancer screening ultimately affects the likelihood of successful treatment and survival, as we would expect.”

This study also has implications for women outside of Japan. It is the first of its kind addressing the benefits of adding ultrasonography on top of mammography in breast cancer screening.

“We believe that J-START is an important trial for several reasons. It is the first randomized trial of population screening with ultrasonography, and was done in asymptomatic women at average risk. They were not pre-selected on the basis of other imaging findings. Earlier studies, most of which were done in the US, involved women at moderate or high risk of breast cancer,” commented Drs. Martin Yaffe and Roberta Jong from University of Toronto, Canada.

“Furthermore, the J-START trial was done in relatively young women. Despite evidence of mammography screening effectively reducing mortality in women in their 40s, this method is seldom recommended or provided for women younger than 50 years. Definitive evidence of whether ultrasonography screening of women from age 40 years can further reduce breast cancer mortality could be an important step.”

The article can be found at: Ohuchi et al. (2015) Sensitivity and Specificity of Mammography and Adjunctive Ultrasonography to Screen for Breast Cancer in the Japan Strategic Anti-cancer Randomized Trial (J-START): A Randomized Controlled Trial.

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Source: The Lancet; Photo: Shutterstock.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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