Background: Prognostic factors from clinical, laboratory and pathological data of patients with colorectal cancer are essential to identify high-risk groups to whom beneficial adjuvant therapy could be given. Endothelin-1, a growth factor, has been associated with the development and spread of solid tumours. This prospective study was performed to determine whether preoperative plasma big ET-1 levels might be useful as a prognostic indicator in patients with colorectal carcinoma.
Method: Sixty-five consecutive patients with colorectal cancer confirmed by biopsy were included prospectively into this study over a 12-month period. Plasma samples from a peripheral vein were obtained prior to surgery. Univariate analysis of survival using age (< or > 70 years), sex, Dukes' stage (A&B versus C), tumour size (< or > 50 mm), vascular invasion and plasma big ET-1 levels was performed and significant factors were then analysed with the Cox regression model.
Results: Three variables, age, Dukes' tumour stage and plasma big ET-1 levels, were found to have prognostic significance (p<0.05). Factors associated with a poorer prognosis were age >70 years (p=0.02), Dukes' C tumours (p=0.04) and plasma big ET-1 levels >4.2 pg/mL (p=0.02). The Cox regression model identified the same three variables as having independent prognostic value for overall survival.
Conclusion: Preoperative plasma big ET-1 levels may be useful in predicting overall survival in patients with colorectal cancer. Plasma big ET-1 levels may be useful in the selection of high-risk lymph node-negative patients with colorectal cancer for adjuvant therapy.