When MRI-guided breast biopsy is canceled due to nonvisualization, follow-up imaging typically finds that the lesion has completely resolved, according to a new study published in Academic Radiology. The authors still recommend follow-up MRI imaging six months later, though, because some lesions do persist.

“Because of the possibility that a malignancy may have been missed at the time of cancellation, a short-term interval follow-up examination remains a prudent course of action,” wrote lead author Samantha L. Heller, MD, PhD, with the department of radiology at the New York University School of Medicine in New York City, and colleagues. “In addition, lesions that have completely resolved or are smaller on follow-up MRI imaging (at least six months post MRI-biopsy cancellation) do not need further follow-up.”

Overall, the authors used to electronic medical records to study 54 biopsies canceled due to nonvisualization from 2007 to 2014. For more than 74 percent of those patients, the suspicious lesion completely resolved by the time of follow-up imaging. For the remaining patients, the lesions persisted after follow-up; more than 42 percent of those patients then underwent a biopsy.

Heller and colleagues also found that more than 70 percent of the patients who had a MRI-guided breast biopsy canceled due to nonvisualization were premenopausal, and more than 86 percent of those patients had their attempted biopsy during a different menstrual cycle week than that first MRI. Should this be viewed as a significant factor?

“Although the majority of premenopausal women in our cohort did have their attempted biopsies at a different cycle week time point than the initial MRI scan, none of these factors was significantly associated with definitive lesion resolution on later follow-up, suggesting that cyclical and hormonal changes cannot be solely responsible for lesions that are not seen at biopsy,” the authors wrote.

Heller et a. noted that their study had certain limitations. For example, numerous patients with canceled biopsies due to nonvisualization did not have follow-up MRI imaging despite it being recommended to them at the time of treatment,” the authors wrote. "Those cases could not be used for this particular study. In addition, management of lesions at follow-up is not necessarily consistent from one reading radiologist to the next. “This may have led to inconsistent approaches to tissue sampling versus follow-up, particularly in the context of stable lesions, a limitation of this retrospective observational study and an area in need of further investigation."