Elevated serum endothelin-1 levels in patients with colorectal cancer; relevance for prognosis.

Background: It has been demonstrated that the Doppler Perfusion Index (DPI) is increased in patients who are at risk of developing liver metastases from colorectal cancer. It has been postulated that a circulating hormonal factor is involved in the relative vasoconstriction throughout the splanchnic bed. Endothelin-1 (ET-1), a potent vasoconstrictor which has been associated with tumor growth and is produced by colorectal tumors, may play an important role in this phenomenon. In this paper the prognostic value of serum ET-1 in colorectal cancer is discussed. Methods: Preoperative serum levels of ET-1 were assessed in three groups of patients: group A underwent resection of the colorectal tumor and remained free of recurrence (n=20); group B developed metachronous liver metastases at least six months after colorectal resection (n=14); and group C presented with colorectal cancer and synchronous liver metastases (n=22). Results: The mean (SD) serum ET-1 levels in groups A, B and C were 1.59 (0.41) pmol/L, 1.70 (0.32) pmol/L and 1.85 (0.47) pmol/L, respectively. These values were significantly different from those of healthy controls (1.22 (0.31), p<0.05). Kaplan-Meier analyses revealed no prognostic value of preoperative serum ET-1 levels. Conclusions: These preliminary results demonstrate that serum ET-1 levels are raised in patients with colorectal cancer. Serum ET-1 levels do not seem to be of prognostic value for survival.