Model predicted likelihood of ADH upgrade to cancer

SAN FRANCISCO — A multivariate model helped predict the likelihood that atypical ductal hyperplasia diagnosed by core needle biopsy would be upgraded to cancer, according to results of a single-center, retrospective study presented at the Breast Cancer Symposium.

Atypical ductal hyperplasia (ADH), a high-risk breast lesion, typically is diagnosed with core needle biopsy.

ADH typically is upgraded to cancer at surgical excision in about 15% to 25% of cases. However, the costs associated with excision and the potential for overtreatment have prompted questions about its routine use.

Alvaro Pena, MD, of Mayo Clinic in Rochester, Minn., and colleagues assessed the clinical, histologic and imaging features typically associated with cancer upgrade, then used their findings to develop their risk prediction model.

All patients were diagnosed with ADH through core biopsy between June 2005 and June 2013, and they subsequently underwent surgical excision.

Pena and colleagues reviewed patients’ electronic records, breast imaging and biopsy slides. They used logistic regression to determine the association between several factors and cancer upgrade.

The analysis included 409 biopsies from patients with core needle biopsy-detected ADH who subsequently underwent surgical excision. The mean age of patients was 58 years (range, 36-86).

Researchers calculated an overall upgrade rate of 16.1% (95% CI, 12.9-20). They determined 10 patients had invasive cancer at excision, whereas 56 had ductal carcinoma in situ.

Pena and colleagues identified three factors strongly associated with upgrade: the estimated percentage of lesion removed, individual cell necrosis and the number of foci of ADH.

The multivariate prediction model showed the likelihood for upgrade was higher among those with less than 50% of the lesion removed (OR=4.2; 95% CI, 1.9-9.1), as well as those with 50% to 75% of the lesion removed (OR=1.4; 95% CI, 0.6-3.2) compared with those with an estimated 90% of the lesion removed.

Those with individual cell necrosis were significantly more likely to be upgraded than those without necrosis (OR=4.6; 95% CI, 2.3-8.9). Upgrade also was more likely among those with ≥2 foci compared with those with 1 focus (OR=2.5; 95% CI, 1.1-5.5).

The predictive model — which showed an average C-statistic of 0.77 — calculated a 5% (95% CI, 1.3-8.7) risk for upgrade among women who did not have individual cell necrosis, along with either 1 focus plus ≥50% lesion removal or ≥2 foci with 90% lesion removal.

“Women whose biopsies meet low-risk criteria might be considered for prevention therapy and surveillance rather than surgical excision,” Pena said during a presentation.

Additional studies to validate the findings are in development, Pena said.

For more information:

Pena A. Abstract #3. Presented at: Breast Cancer Symposium; Sept. 4-6, 2014; San Francisco.

Disclosure: The researchers report no relevant financial disclosures.