Initially metastatic breast carcinoma has a distinct disease pattern but an equivalent outcome compared with recurrent metastatic breast carcinoma.

BACKGROUND: To date, the clinical features and outcomes of patients with initially metastatic breast carcinoma (IMBC) have not been compared with the corresponding characteristics in patients with recurrent metastatic breast carcinoma (RBC). This issue may be particularly relevant to clinical research, as it may shed light on a potential bias with respect to the selection of patients for clinical trials. METHODS: A retrospective analysis of the medical records of 1350 patients with breast carcinoma was performed. Outcome variables included overall survival, response rate, and progression-free survival. RESULTS: One hundred nineteen of 370 patients with metastatic breast carcinoma had IMBC, whereas the remaining 251 had RBC. The median follow-up duration was 39.4 months, and the median overall survival duration was 24 months. With regard to clinical characteristics, patients with IMBC were older than patients with RBC (61.7 years vs. 58.1 years; P < 0.001) and had a higher incidence of lobular carcinoma (15.9% vs. 7.7%; P = 0.018), a greater proportion of T3-4 tumors (58.8% vs. 27.9%; P < 0.001), a higher incidence of bone as the dominant metastatic site (41.2% vs. 21.5%; P < 0.001), a lower incidence of soft tissue as the dominant metastatic site (10.1% vs. 26.7%; P < 0.001), and a similar incidence of the viscera as the dominant metastatic site (48.7% vs. 51.8%; P = 0.78). Median overall survival duration was similar for patients with IMBC (25.1 months) and patients with RBC (23.3 months; P = 0.81). Statistical analyses also revealed nonsignificant differences between patients with IMBC and patients with RBC in terms of response rate (40.7% vs. 35.2%, respectively; P = 0.35) and median progression-free survival duration (10.2 months vs. 9.0 months, respectively; P = 0.58). CONCLUSIONS: Although patients with IMBC and patients with RBC exhibit distinct histologic and clinical characteristics, similar treatment efficacy results and survival outcomes are observed in these two groups.