Grade of ductal carcinoma in situ accompanying infiltrating ductal carcinoma as an independent prognostic factor.

BACKGROUND

Several studies about the relationship between IDC and DCIS have been reported, but no consensus has been reached regarding clinical characteristics and prognostic value.

PATIENTS AND METHODS

We reviewed the medical records of patients who underwent surgery for IDC between 2006 and 2008. DCIS adjacent to IDC was pathologically classified as either high-grade DCIS or non-high-grade DCIS.

RESULTS

Among 1751 IDC patients within the study period, 1384 patients (79.0%) had concomitant DCIS. There was no survival difference between patients with pure IDC and those with IDC and concomitant DCIS. However, patients with high-grade DCIS had worse survival than did patients with non-high-grade DCIS or pure IDC (5-year recurrence-free survival rates for IDC with non-high-grade DCIS, pure IDC without DCIS, and IDC with high-grade DCIS were 97%, 93%, and 86%, respectively; P = .001). This tendency was maintained regardless of estrogen receptor status or histologic grade of IDC. In a Cox regression model, patients with IDC and accompanying high-grade DCIS had a 2.5-fold higher probability of local or distant relapse than did those with IDC and low-grade DCIS (hazard ratio, 2.51; 95% confidence interval, 1.12-5.64).

CONCLUSIONS

The prognosis of patients with invasive breast cancer differed according to the grade of concomitant adjacent DCIS. Accordingly, the grade of adjacent DCIS should be considered as a prognostic factor in the clinical management of patients with breast cancer. However, in our study, the follow-up periods were short to confirm prognostic effect. Further studies are needed.