Background: The prognostic role of serum estrogen level in breast cancer patients is unclear. We investigated the prognostic importance of preoperative serum estradiol (E2) level in postmenopausal women according to their estrogen receptor (ER) status.
Methods: The medical records of 313 postmenopausal breast cancer patients who underwent surgery between 2006 and 2008 at a single institution were retrospectively evaluated. Patients who received neoadjuvant chemotherapy, synchronous bilateral breast cancer, or those with metastasis at diagnosis were excluded. Serum E2 and follicular stimulating hormone (FSH) levels were measured by radioimmunoassay and immunoradiometric assay, respectively, within 3 months prior to surgery. After a median follow-up of 52.0 months (11-77 months), 21 women were found to have metastatic disease.
Results: The overall, median E2 level was 13.0 pg/ml, and was slightly higher in ER-positive than ER-negative (p=0.69). The mean serum E2 level was significantly higher in patients with metastasis (17.41 ± 8.34 pg/ml) than in those without metastasis (13.54 ± 7.58 pg/ml) (p=0.02). Kaplan-Meier analysis using a cut-off of 13 pg/ml showed that, ER negative (p=0.02) but not ER positive (p>0.05) patients with higher E2 level showed significantly poorer metastasis-free survival. Multivariate analysis showed that, the high E2 level of ER negative tumors was an independent negative prognostic factor for metastasis- free survival (HR, 3.32; 95% CI, 1.05 to 10.51; p=0.04).
Conclusions: Higher preoperative serum E2 level had a negative prognostic effect in postmenopausal women with breast cancer, especially in the ER-negative subgroup.