Ultrasound safely omitted in imaging workups of women with breast pain and normal density tissue

Clinicians evaluating women with nondense breasts who are experiencing focal breast pain will find little to no value adding directed ultrasound to digital mammography when the latter is indicated due to screening scheduling.

In fact, the extra imaging may do more harm than good, as it is unlikely to find more cancers than mammography alone in these patients and may spur unnecessary treatments of harmless conditions.  

Michael Cho, MD, MPH, and colleagues at Duke found as much after retrospectively analyzing 413 cases of focal breast pain in 369 women (mean age 53 years) who received both mammography and ultrasound imaging followed by at least two years of imaging follow-up.

Their study posted online Oct. 13 in Academic Radiology.  

In introducing their work, the authors note that, despite the established lack of association between breast cancer and focal breast pain, a diagnostic imaging workup may be requested per American College of Radiology appropriateness criteria.

ACR rates the use of mammography and ultrasound for the evaluation of noncyclical, focal, unilateral or bilateral breast pain in patients 30 years and older as “may be appropriate.”

In women under 30, ultrasound is rated “may be appropriate” and mammography is rated “usually not appropriate.”

Low suspicion level

In the present study, after excluding patients with non-focal, axillary or radiating pain, as well as those with symptoms or histories of trauma or disease, the researchers found that, consistent with previous studies, focal pain very rarely correlated with breast cancer.

No cancers in the study were detected at initial presentation, and fewer than 1 percent of patients who received follow-up screening mammography subsequently developed breast cancer in the same quadrant as the initial pain.

All of these cancers were early stage (0 or 1), and all presented in women with dense breasts.

“There is no way to determine whether the initial presentation of focal breast pain is related to the subsequently detected breast cancer or if it is simply coincidental,” Cho and co-authors write. “These findings and those of previous investigators suggest that radiologists should maintain a low level of suspicion for breast cancer when patients present with focal breast pain.”

Meanwhile, digital mammography turned up discrete lesions at the site of focal pain in 70 percent (14 of 20) of the cases of nondense breasts and in 29 percent (16 of 56) of the cases of dense breasts.

In nondense breasts, directed ultrasound found a lesion in only six of the 20 cases that were negative on digital mammography.

A case for case-by-case?

On the other hand, ultrasound showed its power in evaluating women with dense breasts and focal breast pain.

At two-year follow-up, three of the 413 women (.73 percent), all of whom had dense breasts, developed cancer in the same quadrant as the initial pain.

Further, of lesions detected in dense breasts, 29 percent (16 of 56) were seen with mammography and ultrasound, whereas 71 percent (40 of 56) were detected only with ultrasound, Cho and colleagues report.

In their discussion, the authors note that their study is the largest to evaluate the long-term outcomes and utility of both digital mammography and ultrasound in the workup of primary focal breast pain.

“Given that all subsequent cancers to develop at the site of focal breast pain occurred in women with dense breasts, and benign etiologies were detected by directed ultrasound in women with dense breasts, continuing the practice of combining digital mammography and directed ultrasound in this cohort of women appears prudent,” Cho et al. write.

“However, our data suggest that the use of directed ultrasound in conjunction with digital mammography for the evaluation of focal breast pain in women with nondense breasts is of limited utility and may even contribute to unnecessary intervention because of incidental findings.”