To study the significance of mammographic calcification for local recurrence, metastasis and overall survival for breast cancer patients treated with breast conserving surgery (BCS).

The records of two hundred and four patients of breast carcinoma treated with BCS from January 2004 to May 2014 were reviewed. The results of mammograms and breast untrasound (BUS) tests were available for all those patients. The patients were classified as those without calcification on both mammograms and BUS, those with calcification on mammograms, and those with calcification on BUS but not mammograms; the latter two groups were collectively named patients with calcification. Survival rates were performed with respect to morphologic types and distribution patterns of calcification.

Median follow-up was 85 months. Pathologic characteristics of patients with and without calcification were not statistically different with respect to tumor size, histologic grade, regional lymph node metastasis, hormonal receptor expression, and Her-2 status. Survival analysis found that patients with calcification had significantly higher risk of local recurrence, distant metastasis, and breast cancer-associated death after BCS [relative risk (RR) and 95% CI: 2.46, 1.11-5.44; 2.24, 1.19-4.24; 2.50, 1.06-5.86, respectively]. Subgroup analysis according to morphology of calcification revealed that local relapse free survival (LRFS), disease free survival (DFS), and overall survival (OS) were significantly lower in patients with large/coarse calcification, BUS calcification, and those without calcification, compared with those with microcalcification and pleomorphic calcification. Further survival analyses were performed by the distribution patterns of calcification and showed that patients with calcification of liner and segmental distribution, or calcification spreading along the ducts, had significantly lower LRFS (RR 6.20, 95% CI: 2.26-16.98), DFS (RR 6.81, 95% CI: 2.86-16.20), and OS (RR 9.14, 95% CI: 2.53-33.00), compared with those without calcification. Patients with mammographic calcification of clustered distribution also showed trends of lower LRFS, DFS, and OS, without significant difference. Patients with calcification of liner/segmental distribution were more often accompanied with extensive intraductal component (EIC), compared with those without calcification, with BUS calcification, and with calcification of clustered distribution (P<0.001). The rates of local recurrence were significantly higher in patients with EIC than in those without EIC. The rates of isolated distant metastasis and breast cancer-associated death in patients with calcification who had tumors with or without EIC were not statistically different.

Patients with calcification, especially spreading along the ducts, have higher risk of local failure after BCS, which has negative impacts on long-term survival. Calcification found in BUS tests does not influence the short-and long-term outcome of patients treated with BCS. Existence of EIC is a predictive factor of local failure in patients with calcification treated with BCS.