6-month follow-up diagnostic mammograms recommended for women with probably benign lesions

May 8, 2008

Radiologists can, with confidence, recommend a six-month follow-up diagnostic mammogram rather than an immediate biopsy for patients with “probably benign” breast lesions, a new study emphasizes.

The study found that six-month short-interval follow-up examinations had an 83% sensitivity, which is similar to the sensitivity of other diagnostic mammograms, said Erin J. Aiello Bowles, MPH, lead author of the study from the Group Health Center for Health Studies. High sensitivity means identifying a high proportion of “true positives” (actual cancer cases) and a low proportion of “false negatives” (cases mistakenly deemed benign).

The study included 45,007 initial short-interval follow-up mammograms. “Short-interval follow-up mammograms are done to monitor for changes in ‘probably benign’ breast lesions (findings seen on mammograms that have a very low probability of being cancer). Because the probability of cancer is so low, we don’t want to put the patient through an unnecessary biopsy, which is an invasive procedure that increases both patient anxiety and medical costs,” said Aiello Bowles. “At the same time, we want to closely monitor these patients, because changes in ‘probably benign’ lesions occasionally mean cancer, and we want to detect the cancers as early as possible,” she said. In the study, 360 women with “probably benign” lesions were diagnosed with breast cancer within six months; and 506 women were diagnosed with cancer within 12 months (altogether about one in 100 of the “probably benign” lesions), Aiello Bowles said.

“The Breast Imaging-Reporting and Data System (BI-RADS) recommends that women with a BI-RADS category 3 (probably benign) lesion get a six-month diagnostic mammogram, with follow-up continued for the next two to three years until long-term stability is demonstrated,” said Dr. Edward Sickles, a coauthor and radiologist involved in the study from the University of California San Francisco. “This study emphasizes that radiologists and patients need to follow that recommendation,” he said.

Source: American Roentgen Ray Society