Diagnosing Breast Cancer: Lesion and Patient Characteristics Associated With Malignancy After a Probably Benign Finding on Community Practice Mammography

The objective of a recent study was to perform a retrospective review of lesions categorized as “probably benign” initially and then diagnosed as malignancy on follow-up mammograms.

Methodology
The study included 129 mammographic lesions categorized as “probably benign” initially, but were subsequently diagnosed as malignant, and 129 control mammographic lesions that were categorized as “probably benign” and deemed to be stable and benign after 3-year follow-up.

A retrospective review of features of lesions and characteristics of patients was performed by a breast imaging specialist in community practice.

Results
258 lesions that were categorized as “probably benign” represented 2.1% of total screening mammograms interpreted in the community practice.

During the follow-up period, 8.8% of “probably benign” category lesions were diagnosed as carcinoma.

Cancer yield for lesions that were categorized as “probably benign” was significantly higher among older patients, postmenopausal patients, and patients with a family history of breast cancer or history of breast biopsy.

Breast density and use of hormonal replacement therapy did not affect the cancer yield.

Microcalcifications, when categorized as probably benign, were more likely to be carcinoma on follow-up.

Masses that were categorized as “probably benign” were more likely to yield cancers when the margins of masses were obscured or indistinct. There were no amorphous or suspicious microcalcifications that were categorized as probably benign.

Conclusions
Morphologies of microcalcifications and margins of masses, along with patients’ risk factors, can predict outcomes of lesions that are categorized as probably benign.

Reviewer’s Comments
The American College of Radiology BI-RADS category 3 allows radiologists to recommend imaging follow-up on “probably benign” lesions instead of recommending biopsies after complete mammographic workup.

However, radiologists must perform necessary additional diagnostic workups and must follow strict criteria.

In this article, the cancer yield was 8.8% among lesions that were categorized as “probably benign,” which is significantly higher than the recommended 1.4%.

This result is suggestive of possible misuse of BI-RADS category 3 and potential delay in diagnosis and negative impact on prognosis.

Therefore, it is extremely important for radiologists to perform complete mammographic workups before categorizing lesions into BI-RADS category 3 with short-term follow-up recommendation.

Author: Bokran Won, MD
Reference: Lehman CD, Rutter CM, et al. Lesion and Patient Characteristics Associated With Malignancy After a Probably Benign Finding on Community Practice Mammography. AJR; 2008; 190 (February): 511-515