Abstract P2-10-35: The grade of accompanying DCIS in IDC as important prognostic factor

Abstract

Abstract Backgrounds: The issue of whether concomitant ductal carcinoma in situ (DCIS) affects the prognosis of with invasive breast cancer is important but studies of this have reported inconsistent results. So we aimed to assess the character and prognostic difference in infiltrating ductal carcinoma (IDC) according to accompanying DCIS status. Methods: We reviewed the medical records of the patients who underwent surgery for IDC. Male patients, patients who had received neoadjuvant chemotherapy, patients with synchronous bilateral breast cancer, follow-up periods <6months or those with other malignancies were excluded from the study. In cases in which a DCIS component was present in IDC, the degree of differentiation and the presence of necrosis were assessed to subdivide DCIS into two groups; low and high grade. Results: A total of 1751 patients were included, and 1384 patients (79.0%) had concomitant DCIS; 337 had low-grade DCIS, and 1047 patients had high-grade DCIS. The low-grade DCIS group had a significantly lower TNM stage than the high-grade DCIS group. The majority of cases with low-grade DCIS, were ER-positive (85.2%), PR-positive (81.3%) and had low Her-2 (98.7%). When we analyzed the survival rates according to the presence of DCIS, no statistical significance was founded. However, a subgroup analysis showed that the patients with low-grade DCIS survived significantly longer than other patients, whereas those with high-grade DCIS had poorer survival (5 year event-free survival rate; low-grade DCIS vs. without DCIS vs. high-grade DCIS, 97% vs. 93% vs. 86%, p = 0.001). Specially, in patients with lymph node involvement, accompanying high-grade DCIS was independent predictor distant metastasis (HR 5.0, p = 0.026, 95% CI 1.21–20.92). Conclusion: The important factor that affect prognosis of IDC with DCIS is not the presence itself of DCIS component but the grade of DCIS. The patients with low-grade DCIS had a good prognosis and those with high-grade DCIS had a poor prognosis. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-10-35.