The addition of ultrasonography to mammography significantly improves the rate of detection of breast cancers in Japanese women, according to trial findings published online in The Lancet on November 5th.
Findings showed that combining ultrasound with mammography resulted in correctly detecting cancer in more than 9 of 10 cases (91% sensitivity), whereas for women given mammography alone, just more than three quarters of tests correctly identified breast cancer (77% sensitivity).
These data are important because mammography screening alone may not be sufficient for screening Asian women, owing to the fact that they characteristically have higher-density breasts than women of other ethnicities and because breast cancer tends to present at an earlier age in Japan than in Europe or the United States. The accuracy of mammography is reduced both in women with high-density breast tissue and in young women.
Therefore, the use of adjunctive ultrasonography could offer a low-cost way to increase sensitivity and detection rates of early cancers in women with dense breast tissue, note the authors, led by Noriaki Ohuchi, MD, PhD, of Tohoku University Graduate School of Medicine, Miyagi, Japan.
“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 Dr Ohuchi in a statement. “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.”
Higher Detection of Invasive Cancers
In the Japan Strategic Anti-cancer Randomized Trial (J-START), Dr Ohuchi and colleagues assessed the efficacy of adjunctive ultrasonography in breast cancer screening for Japanese women aged 40 to 49 years.
They enrolled 72,998 women between 2007 and 2011; 36,859 were assigned to ultrasound testing plus mammography (the intervention group), and 36,139 were assigned to the control group of mammography alone. Screening was conducted twice during a 2-year period.
The mean age of participants was 44 years; 3344 (4.6%) participants reported a history of breast cancer in first-degree female relatives, and 917 (1.3%) reported having had one or more benign breast conditions.
| Mammography Alone (Control Group) | Mammo + Ultrasound (Intervention Group) | |
| Sensitivity | 77% | 91.1% |
| Specificity | 91.4% | 87.7% |
Significantly more cancers were detected at screening in the ultrasonography group compared with the mammography alone group, at 184 and 117, respectively. And detected cancers were significantly more likely to be stage 0 or 1 in the intervention than in the control arm (71.3 vs 52.0%).
Fewer interval neoplasms were diagnosed among women in the ultrasonography group compared with those screened by mammography alone, at 18 versus 35, a significant difference.
The J-START investigators conclude that adjunctive ultrasonography could offer a low cost way to improve sensitivity and detection rates of early-stage cancers in women with high-density breast tissue and young women, groups in which the accuracy of mammography is reduced.
In a related commentary, Martin Yaffe and Roberta Jong, from the University of Toronto in Ontario, Canada, say that J-START is an important trial as it is “the first randomized trial of population screening with ultrasonography, and was done in asymptomatic women at average risk, who were not preselected on the basis of other imaging findings.”
Moreover, the trial was conducted in “relatively young women”, they say, adding that “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.
Studies are now beginning to show the benefit is even greater in women with dense breasts for whom the sensitivity of mammography for detecting breast cancer is decreased. Bottom line, the combination of screening mammography PLUS ultrasound improves cancer detection. There is always the concern about false positives and too many unnecessary biopsies, but detection is the first and most important step in our fight against breast cancer!
