Long-term Surveillance of Ductal Carcinoma in Situ Detected with Screening Mammography versus US: Factors Associated with Second Breast Cancer
Seung Hee Choi, Ji Soo Choi , Boo-Kyung Han, Eun Young Ko, Eun Sook Ko, Ko Woon Park
Author Affiliations
From the Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 06351, Korea.
Address correspondence to J.S.C. (e-mail: jisoo.choi@samsung.com).
Published Online:Apr 30 2019https://doi.org/10.1148/radiol.2019181844
See editorial byAmy M. Fowler
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Abstract
In patients with screening mammography–detected ductal carcinoma in situ (DCIS), higher nuclear grade and dense breast were associated with second breast cancer; in patients with screening US–detected DCIS, human epidermal growth factor receptor 2 positivity was associated with second breast cancer.

Background
The relationship between method of breast cancer screening (mammography or US) and survival outcome in patients with screening-detected ductal carcinoma in situ (DCIS) has not been determined.

Purpose
To investigate whether different methods of breast cancer screening are associated with different survival outcomes in patients with screening-detected DCIS and to evaluate clinical-pathologic and imaging factors associated with second breast cancer.

Materials and Methods
We retrospectively identified women who underwent surgery to treat DCIS initially detected with screening mammography or US between July 2004 and December 2011 in a single institution. Overall survival (OS) and disease-free survival (DFS) were assessed. Factors associated with second breast cancer (invasive carcinoma or DCIS) were found with multivariable Cox proportional hazards regression analysis. Subgroups were analyzed according to screening method.

Results
A total of 814 women (median age, 47 years; age range, 25–81 years) were included; 627 underwent treatment for screening mammography–detected DCIS (mammography-detected group), and 187 underwent treatment for screening US–detected DCIS (US-detected group). During follow-up (median, 7 years; interquartile range, 5–8 years), 26 ipsilateral and 26 contralateral second breast cancers (6.4%, 52 of 814) were found, with 44 in the mammography-detected group and eight in the US-detected group. The overall 5-year OS and DFS rates were 100% and 95.3%, respectively. DFS rates did not differ according to screening method (P = .21, 5-year DFS rates were 94.9% in the mammography-detected group and 96.5% in the US-detected group). In the mammography-detected group, higher nuclear grade (intermediate grade: hazard ratio [HR], 5.7; 95% confidence interval [CI]: 1.3, 24.3; P = 0.02) (high grade: HR, 8.0; 95% CI: 1.9, 34.2; P = .01) and dense breast (HR, 3.5; 95% CI: 1.1, 11.4; P = 0.04) were associated with second breast cancer. In the US-detected group, human epidermal growth factor receptor 2 positivity was associated with second breast cancer (HR, 9.2; 95% CI: 2.2, 38.5; P = .002).

Conclusion
Disease-free survival of patients who underwent treatment for screening-detected ductal carcinoma in situ (DCIS) did not differ according to screening detection method. In patients with screening mammography–detected DCIS, higher nuclear grade and dense breast were associated with second breast cancer, and in patients with screening US–detected DCIS, human epidermal growth factor 2 positivity was associated with second breast cancer.

© RSNA, 2019