AJR: Breast ultrasound surveillance tops biopsy for women under 30

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Women younger than 30 years of age with focal breast signs or symptoms can be safely and accurately followed using targeted ultrasound surveillance, according to a study published in the December issue of American Journal of Roentgenology.

The American College of Radiology Appropriateness Criteria recommends ultrasound as the first study for young women, except those at high risk, with focal signs or symptoms, and the model is widely used. However, few outcomes data exist to validate the model. “Questions remain regarding the accuracy of ultrasound and the need for concurrent mammography in this patient population,” according to Vilert A. Loving, MD, of Seattle Cancer Care Alliance and the department of radiology at University of Washington Medical Center in Seattle, and colleagues.

Loving and colleagues sought to assess the accuracy of ultrasound as a primary imaging study for malignancy detection in women younger than 30 with focal breast signs or symptoms and to evaluate its safety as short-term followup for symptomatic lesions characterized as probably benign.

The researchers reviewed electronic records to retrospectively identify all breast ultrasound studies performed at the center between Jan. 1, 2002 and Aug. 30, 2006, in women younger than 30 years. From this group, Loving and colleagues identified 830 women presenting with focal breast signs or symptoms, excluding high-risk women and those with a known cancer or lesion identified at an outside facility.

When radiologists characterized a lesion as BI-RADS category 1 or 2 on the initial ultrasound exam, they did not recommend additional imaging or tissue sampling. They recommended ultrasound-guided core needle biopsy for BI-RADS category 4 or 5 lesions.

Radiologists offered women with BI-RADS category 3, probably benign, lesions several options: ultrasound surveillance at 6, 12 and 24 months; core needle biopsy or surgical excision.

The researchers determined benign and malignant outcomes by biopsy and 24 months of follow-up imaging. They also checked the regional tumor registry for at least 24 months to locate malignancies diagnosed at other medical institutions. Any invasive carcinoma or ductal carcinoma in situ was characterized as malignant.

The study cohort comprised 1,091 lesions in 830 women (mean age, 24 years), who underwent 865 ultrasound exams. Radiologists assessed 526 women with BI-RADS category 1 or 2 lesions.

The BI-RADS assessment was category 3 in 140 patients, reported Loving and colleagues. Twenty-two women completed 24 months of follow-up ultrasound surveillance, and all were stable and benign. Forty-six women elected to undergo biopsy, and 72 women did not complete imaging or surgical followup. Researchers noted no malignancies in any lesion assessed as BI-RADS category 3.

One hundred sixty-three patients were assessed with BI-RADS category 4 lesions, with 155 women undergoing biopsy and two women diagnosed with malignant lesions. The single category 5 lesion was diagnosed as malignant via biopsy.

Overall sensitivity of targeted ultrasound was 100 percent, and specificity was 80.5 percent.

Loving and colleagues noted that the results suggest that targeting mammography to “highly suspicious cases is a safe practice in this patient population.” The researchers added, ”Surveillance has advantages over biopsy because of its lower morbidity.”

The authors identified several limitations to the study. Specifically, the retrospective single-site study employed radiologists specializing in breast imaging to perform the ultrasound exams. They suggested that additional studies should be performed to determine whether the results are generalizable to other practice settings. The low patient compliance rate with recommended surveillance presented a source of concern, and the authors recommended further efforts to improve compliance.

The incidence of breast malignancy was 0.4 percent in the study of women younger than 30 years, reported Loving and colleagues, who added that finding no malignancies in women with probably benign lesions supports “ultrasound surveillance as a safe alternative to tissue sampling in this setting.”