Breast lumps found between scheduled screening mammograms are better evaluated with targeted ultrasound than with repeat mammography, as the latter doesn’t add value beyond the former and so may only increase expense as well as radiation exposure.

The study behind the conclusion is running in the July edition of the American Journal of Roentgenology. It was conducted at St. Joseph’s Health Care in London, Ontario, and led by radiologist Stephanie Leung, MD, of the University of Western Ontario.

The team reviewed the cases of women who were examined at their institution for a new palpable lump with both mammography and targeted ultrasound between January 2005 and December 2012. The patients also had a negative mammogram within the previous six to 12 months.

Some 612 patients with a total of 618 palpable lumps met these criteria. The mean age of the women was 55.9 ± 11.2 years.

The researchers found that, in 314 of 618 cases (50.8 percent), there was a sonographic finding, a mammographic change or both in the region of the palpable lump.

Most notably, the ultrasound detected a finding in 311 cases (50.3 percent)—while the repeat mammography detected a change in only 80 cases (12.9 percent).

Meanwhile, of the 314 cases with imaging findings, 234 findings (74.5 percent) were detected by ultrasound alone.

Also, 80 lesions were biopsied, and 48 of them (60.0 percent) were positive for malignancy. The repeat mammogram findings were unchanged for 10 of these lesions.

Among the study’s limitations, the authors acknowledge the lack of tomosynthesis technology during the study period. “Our results therefore need to be duplicated in a larger study, perhaps with the use of tomosynthesis in addition to routine mammography compared with ultrasound,” Leung and colleagues write.

Be that as it may, “targeted ultrasound yielded statistically significantly more diagnostic information than did repeat mammography,” the authors emphasize. “This agrees with other studies, which found that a significant number of palpable abnormalities that were detected by ultrasound were mammographically occult.”

Leung et al. add that, in cases of palpable lump found between screenings, if the ultrasound reveals normal breast tissue—or if it shows a benign or probably benign finding (BI-RADS category 2 or 3)—“then the diagnostic workup can stop here with clinical or imaging follow-up accordingly.”