Survival analysis between patients with invasive ductal and invasive lobular breast cancer.

OBJECTIVE: Differences in overall survival (OS) and disease-free survival (DFS) between patients with invasive ductal (IDC) and invasive lobular breast cancer (ILC) are controversial.

STUDY DESIGN: The study population was selected from a database of 5,689 female patients with invasive breast cancer. In order to focus on the impact of tumour histology, all primary metastatic patients and patients with adjuvant chemotherapy or anti-hormonal treatment were excluded. Only patients with pure invasive lobular and invasive ductal histology were included.

RESULTS: Multivariate survival analyses of 2,058 eligible patients confirmed tumour histology as an independent prognostic factor for OS in invasive breast cancer (p = 0.046) but not for DFS (p = 0.599). Kaplan-Meier survival analysis of OS between IDC and ILC patients showed a statistically significantly better OS for patients with ILC (p = 0.0302). DFS was not statistically different (p = 0.6659) between IDC and ILC. Univariate survival analyses of tumour size, tumour grading and nodal status in our study population were highly statistically significant for OS and DFS (p < 0.0000).

CONCLUSION: Patients in our study population with ILC have significantly better OS than patients with IDC. Differences in DFS are not statistically significant.