Prognostic significance of thymidylate synthase in patients with metastatic colorectal cancer who receive protracted venous infusions of 5-fluorouracil

Background. This study was conducted to evaluate the prognostic significance of thymidylate synthase (TS) expression in the tumor tissue of patients with metastatic colorectal cancer (CRC) who received protracted venous infusions of 5-fluorouracil (5-FU). Methods. We retrospectively analyzed the prognostic value of TS expression as compared with other clinical prognostic factors in 57 patients with metastatic CRC. Results. On univariate analysis, survival was significantly related to TS expression (low vs high; P = 0.0015), alkaline phosphatase (ALP) level (<300 vs ≥300 IU/l; P = 0.0037), performance status (0 or 1 vs 2 or 3; P = 0.0073), and white blood cell count (<10 000/mm3 vs ≥10 000/mm3; P = 0.0001), with number of metastatic sites (1 vs ≥2; P = 0.06) approaching significance. On multivariate analysis, survival was significantly related to TS expression (hazard ratio [HR], 2.97) and ALP level (HR, 2.26). Conclusion. In patients with metastatic CRC who received protracted venous infusions of 5-FU, TS expression was related to survival independently of other established clinical prognostic factors.