Qualitative Radiogenomics: Association Between BI-RADS Calcification Descriptors and Recurrence Risk as Assessed by the Oncotype DX Ductal Carcinoma In Situ Score.

OBJECTIVE

Treatment of ductal carcinoma in situ (DCIS) is controversial given the variable recurrence and progression to invasive carcinoma. Identifying women who would benefit from adjuvant radiation therapy on the basis of their recurrence risk may allow more individualized management strategies. The Oncotype DX Breast DCIS Score-which we refer to here as the "DCIS score"-is a validated surrogate marker of local recurrence. This study evaluated the association between BI-RADS mammographic calcification descriptors and the DCIS score.

MATERIALS AND METHODS

Fifty-eight women diagnosed with DCIS presenting with calcifications who had Oncotype DX Breast DCIS assay results were identified. Pretreatment BI-RADS mammographic calcification features were collected including morphology, distribution, and maximum span. The association between calcification descriptors and DCIS score was assessed with logistic regression modeling. Mean DCIS scores were calculated for calcification features significantly associated with DCIS score. All analyses were adjusted for patient age, DCIS grade, and progesterone receptor status.

RESULTS

Of the suspicious calcifications that proved to represent DCIS, 19.0% were amorphous; 25.9%, coarse heterogeneous; 39.7%, fine pleomorphic; and 15.5%, fine linear or fine linear branching in morphology. The mean DCIS scores by calcification morphology were 22.3, 35.5, 36.7, and 44.1, respectively. Amorphous calcification morphology had a significantly lower adjusted mean DCIS score compared with fine pleomorphic morphology (p = 0.01) and fine linear or fine linear branching morphology (p = 0.02). The adjusted odds ratio (OR) of intermediate or high risk of recurrence (defined as a DCIS score ≥ 39) was significantly higher for women with fine pleomorphic calcifications (OR = 53.1, p = 0.01) and for those with fine linear or fine linear branching calcifications (OR = 24.0, p = 0.04) than for women with amorphous calcifications.

CONCLUSION

Women with amorphous calcification morphology had the lowest DCIS scores compared with women with fine pleomorphic and fine linear or fine linear branching morphologies. Both fine pleomorphic and fine linear or fine linear branching morphologies were associated with higher odds of intermediate or high risk of recurrence. These findings suggest mammographic features are potential biomarkers of DCIS recurrence and could help individualize treatment decisions.