Increased likelihood of mastectomy in human epidermal growth factor receptor 2-positive ductal carcinoma in situ.

Patients with human epidermal growth factor receptor 2 (HER2neu)-positive breast invasive cancer are known to have larger, more aggressive tumors. Little research exists on the relationship between HER2neu status and extent of ductal carcinoma In Situ (DCIS). A retrospective review of a single-institution database was performed for patients with DCIS between the years 2002 and 2011. A single blinded breast radiologist reviewed preoperative imaging. Pathology was reviewed for extent of DCIS. Primary outcome was mastectomy. Multivariate logistic regression was used to determine adjusted mastectomy risk. There were 166 cases, 34 HER2neu-positive. HER2neu receptor-positive patients had larger lesions on imaging: 4.0 versus 2.7 cm, by 2.9 versus 1.5 cm (P = 0.0499 and 0.0182). HER2neu-positive patients with DCIS were more likely than HER2neu-negative to undergo mastectomy than lumpectomy (53 vs 28%, P = 0.006). Pathology revealed a trend toward larger lesions in HER2neu-positive patients (2.96 vs 2.22 cm, nonsignificant). Patients with HER2neu-positive disease were three times more likely to undergo mastectomy (odds ratio, 2.9; 95% confidence interval, 1.23 to 6.78). Patients with HER2neu-positive DCIS had greater extent of disease by imaging and were more likely to undergo mastectomy than HER2neu-negative. These findings will help surgeons counsel patients on surgical treatment.