Digital Mammography Detects More High-Risk Lesions

Moving from film-screen mammography (FSM) to digital mammography (DM) is associated with a three-fold increase in detection of high-risk breast lesions, according to a study published in the American Journal of Roentgenology.

Researchers from the University of Michigan undertook a retrospective study to evaluate if there would be an increase in detection rates of these lesions as the university transitioned from FSM-only screening in 2004 to DM-only screening in 2010.

The researchers identified 142 cases of atypia or lobular neoplasia (LN) diagnosed in women who had mammographic calcifications between January 2004 and August 2010. There were 82 (57.7 percent) cases of atypical ductal hyperplasia; 17 (12 percent) atypical lobular hyperplasia; 25 (17.6 percent) lobular carcinoma in situ (LCIS); 12 (8.5 percent) atypia and LCIS; and six (4.2 percent) other atypia.

Women who had lesions that had been upgraded to cancer at excisional biopsy, lesions in women with ipsilateral cancer within two years of mammography, and lesions that presented as a mass only were excluded from the study.

The researchers found of the 142 cases of atypia or LN, 52 (36.6 percent) were detected using FSM and 90 (63.4 percent) were detected using DM. The DM detection rate was higher (1.24/1000 mammographic studies) than FSM (0.37/1000 mammographic studies). The detection rate by year ranged between 0.21 and 0.64 per 1000 mammographic studies for FSM and between 0.32 and 1.49 per 1000 mammographic studies for DM. The median size of DM and FSM calcifications were 8mm and 7mm, respectively. Clustered amorphous or indistinct calcifications were the most common appearance on both FSM and DM.

While the detection rate was higher with DM, the authors cautioned there may be disadvantages, such as higher recall rates and lower positive predictive value. As well, more women would undergo biopsies.

“Improved detection may allow enhanced screening, risk reduction treatment, and possibly breast cancer prevention. However, increased detection of high-risk lesions may also result in oversurveillance and treatment,” they concluded.