Does concomitant ductal carcinoma in situ affect the clinical outcome in breast cancer patients with invasive ductal carcinoma: An Asian perspective

Background Ductal carcinoma in situ (DCIS) is an established precursor to invasive ductal carcinoma (IDC) and its coexistence with IDC appear to favor reduced biological aggressiveness. Its prognostic implication and ability to affect clinical outcome has been understudied in Asia. This study aims to explore if concomitant DCIS affects the clinical behavior and outcomes among Asians. Aim Stages I to III breast cancer patients with histological proven IDC, diagnosed and treated in a single institution from June 1, 2004 to June 30, 2014 were included in this study. Statistical analyses were conducted using Χ2 test, independent t test, multivariate logistic regression and Kaplan–Meier test. Methods and Results A total of 818 patients were identified, including 224 and 594 patients with isolated IDC (No‐DCIS) and IDC with coexisting DCIS (IDC‐DCIS) respectively. Patients with IDC‐DCIS were found to have smaller tumors (median: 22 mm, p ≤ .01), estrogen receptor positivity (p = .001), progesterone receptor positivity (p