Survival of patients with metastatic breast carcinoma: importance of prognostic markers of the primary tumor

Abstract

Background: Women with metastatic breast carcinoma have a highly variable clinical course and outcome. Intrinsic genetic heterogeneity of the primary breast tumor may play a role in this variability and may explain it in part. Therefore, the authors tested the hypothesis that the characteristics of primary breast tumors are important determinants of prognosis and survival in patients with metastatic breast carcinoma.

Methods: The prognostic significance of the biology of the primary tumor for outcome in patients with metastatic breast disease was assessed in 346 patients with lymph node positive breast carcinoma who developed distant, recurrent disease. Traditional prognostic indicators (age, tumor size, number of involved lymph nodes, sites of recurrence, disease free interval [DFI], adjuvant treatments, estrogen receptor [ER] expression, progesterone receptor [PgR] expression, S-phase fraction [SPF], and DNA ploidy), together with three newer biologic markers (c-erbB-2, p53, and bcl-2) were assessed. Sites of recurrence were defined as nonvisceral (bone and locoregional lymph nodes) or visceral (lung, liver, brain, and other organs).

Results: The median duration of survival was 17.8 months (95% confidence interval, 15.2-21.5 months). Univariate analysis showed that age > 50 years, visceral disease, and shorter DFI were associated significantly with poor outcome (P < 0.05). In addition, the molecular phenotype of the primary breast tumor was significant, with primary tumors that showed ER negativity and PgR negativity, high SPF, aneuploidy, accumulation of p53 protein, and lower bcl-2 expression, together with c-erbB-2 overexpression, all associated with a poorer clinical outcome (P < 0.05). In a multivariate analysis, older age, visceral disease, shorter DFI, PgR negativity, high SPF, and lower bcl-2 expression were significant predictors of worse survival (P < 0.05).

Conclusions: In addition to traditional risk factors, bcl-2 negativity was associated significantly with a worse clinical outcome. Biologic features of primary tumors were correlated independently with outcome after first recurrence in patients with metastatic breast carcinoma and may be used as indicators of prognosis in the metastatic setting.