Influence of ductal carcinoma in situ on the outcome of invasive breast cancer. A prospective cohort study.

BACKGROUND

Ductal carcinoma in situ (DCIS)-associated invasive ductal carcinoma (IDC) is present in a large number of patients with breast cancer. However, the association between these two entities has not been studied in detail. The aim of this study is to compare the clinical and histopathological factors associated to recurrence of IDC with those of DCIS-associated IDC (IDC + DCIS).

MATERIALS AND METHODS

A prospective observational longitudinal study of 464 patients was performed between 2010 and 2015. Patients with IDC and DCIS + IDC were included and analyzed.

RESULTS

IDC + DCIS was present in 243 patients (52.4%). No difference on histopathological characteristics were found, only Grade I and II of invasive component were more frequent in patients with IDC + DCIS than those with IDC (p  =  0.038). No differences on recurrence were found between the main groups (p = 0.256). For patients who received neoadjuvant chemotherapy, those with IDC + DCIS had lower response than those with IDC alone (p  =  0.014). No differences between the main groups were found on recurrence (p = 0.256). For patients who received neoadjuvant chemotherapy, recurrence was present in 19 patients (30.6%) in the IDC group in contrast to 5 (12.2%) in the IDC + DCIS group (p = 0.030). Mortality was present in 15 patients (24.2%) in the IDC group in contrast to 3 (7.3%) in the IDC + DCIS group (p = 0.027). At 7 years, 80.8% patients were alive: 71.9% from the IDC group and 92.7% from the IDC + DCIS group.

CONCLUSIONS

The presence of DCIS seems to be indicative of a benign behavior in patients who receive neoadjuvant chemotherapy. Longer DFS and higher overall survival were found in the IDC + DCIS group despite presenting with a lower response to chemotherapy. These findings help us identify patients with better prognosis in breast cancer.