Estrogen as a prognostic factor on liver metastasis from colorectal cancer.
506 Background: Estrogen plays an important role in some cancer. However, previous studies about the influence of estrogen on colorectal cancer (CRC) have been conflicting, especially rare reports on liver metastasis. This study tries to explore the prognostic impact of estrogen on CRC with liver metastasis. Methods: Eighty six patients with CRC including 43 synchronous liver metastases were studied. Estrogen receptor-beta (ER-beta) were assayed by immunohistochemistry (IHC) in liver metastasis tissues, colorectal cancer tissues and normal tissues. And the serum estrogens were detected by radioimmunoassay (RIA) in 30 patients with CRC including 14 synchronous liver metastases. After follow-up, the relationship between ERβ, estrogen and survival time were analyzed. Results: The positive rates of ER-beta in liver metastases tissues, CRC tissues and normal tissues were 39.5% (17/43), 39.5% (34/86) and 62.8% (54/86), respectively; and significant differences were found between liver metastasis (P=0.012) or CRC (P=0.002) with normal tissues. The 1-, 2-, 3-and 5-year survival rates for ER-beta positive patients were 97%, 79%, 71% and 51%, respectively comparing with 82%, 59%, 55% and 40%, respectively for ER-beta negative patients (P=0.190). In contrast, the 1-, 2-, 3- and 5-year survival rates in liver metastasis group were 77%, 37%, 31% and 23%, respectively; and 93%, 64%, 57% and 57%, respectively for ER-beta positive patients comparing with 67%, 19%, 14% and 7%, respectively for ER-beta negative patients (P=0.004). Serum estrogen levels in patients with liver metastases were significantly lower than those without liver metastasis (P=0.012) and Pearson Correlation showed that there was a moderate positive correlation between level of serum estrogen and survival time (P=0.006). Conclusions: CRC liver metastasis patients with positive ER-beta have a better survival, which indicates estrogen is a protective factor for CRC liver metastasis patients. But more study is needed to show estrogen would be a protective factor for CRC patients.