Clinical outcome after selective treatment of patients diagnosed with ductal carcinoma in situ of the breast

Background: The effect of treatment of patients diagnosed with ductal carcinoma in situ (DCIS) of the breast was evaluated, and factors associated with local recurrence were assessed. Methods: The study involved 504 patients treated by means of wide local excision alone (WLE) (n = 91), wide local excision and radiotherapy (WLE+RT) (n = 119), or mastectomy (n = 294) at the Netherlands Cancer Institute between 1986 and 2005. Clinical, pathological, and follow-up data were evaluated. Results: The median time to follow-up was 6.7 years. The 8-year overall local recurrence rate was 12% after breast-conserving treatment (BCT) [15.6% after WLE and 8.8% after WLE+RT (P = 0.161)] and 0.9% after mastectomy (P < 0.0001). In total, 18 (66.7%) invasive local recurrences and 9 (33.3%) DCIS local recurrences occurred. The 8-year distant metastasis rate was 4% after BCT [4.3% after WLE and 4.2% after WLE+RT (P = 0.983)] and 0.9% after mastectomy (P = 0.048). Median tumor extent was 10, 15, and 35 mm for patients treated with WLE, WLE+RT, and mastectomy, respectively. Margins were involved in 6.4% of all patients. Factors associated with local recurrence were age younger than 40 years (HR 8.66), surgical margin involvement (HR 5.75), WLE (HR 26.77), and WLE+RT (HR 7.42). Conclusion: BCT of DCIS bears the risk of residual disease progressing into invasive local recurrence and distant metastasis. A re-excision or mastectomy is therefore desired in all patients with unclear margins. Mastectomy treatment is associated with optimal local control and might be considered for patients younger than 40 years who are at high risk of local recurrence.