Prognostic factors for stage IV hormone receptor-positive primary metastatic breast cancer

Background

The purpose of this work was identify potential prognostic factors for survival in patients with primary metastatic hormone receptor-positive breast cancer undergoing endocrine therapy (ET) as first-line treatment.

Methods

We investigated the clinical and pathological characteristics of 69 newly diagnosed stage IV hormone receptor-positive breast cancer patients undergoing ET between 1999 and 2009, and correlated these factors with disease progression and overall survival.

Results

Multivariate regression analysis revealed that progesterone receptor (PgR) positivity (hazard ratio (HR) 0.248; p = 0.001) and clinical benefits of first-line ET (HR 0.386; p = 0.008) were significant prognostic factors for survival. When first-line ET was not effective, patients for whom second-line ET was effective survived significantly longer than those for whom second-line ET was not effective (median survival time, 45.3 vs. 25.8 months; p = 0.0411).

Conclusions

PgR positivity and clinical benefits of first-line ET were independent prognostic factors for patients with hormone receptor-positive stage IV breast cancer. Moreover, the benefits of second-line ET in patients with a tumor resistant to first-line ET suggests the existence of drug-specific resistance to ET.