Prognostic value of thymidylate synthase and cox-2 expression in colorectal cancer patients' tumors

Abstract

3731 Background: Colorectal cancer (CRC) is a major health problem in the world for both men and women due to its high incidence and limited benefit with chemotherapy when the disease recurs. There is a need for progress in assessment of the prognosis of patients and predict who would benefit from treatment. In this study, the value of molecular markers thymidylate synthase (TS) and cox-2 were evaluated as prognostic predictors in patients with stage II and III CRC. Patients and Methods: We retrospectively analyzed the prognostic value of TS and cox-2 in 49 patients with stage II (n=23) and III (n=26) CRC. They were treated with either surgery alone or surgery followed by adjuvant fluorouracil and leucovorin chemotherapy in Marmara University Hospital, Medical Oncology Department between April 1997 and 2003. A specialized pathologist evaluated these markers using immunohistochemical techniques. Samples were scored as high and low TS and Cox-2 intensity according to their staining properties.Low intensity: No staining or less than 10% of tumoral cells are stained. High intensity: More than 10% of tumoral cells are stained. Results: High TS intensity was found in 20.4% of tumor samples with mucinous component and in 64.1% without mucinous component (p=0.01). In patients whose tumor samples had low or high TS intensity 5 year overall survival was 61.5% and 37.5% respectively (p=0.86). Also with low or high cox-2 intensity, overall 5-year survival did not improved (40% vs 70.6%) statistically (p=0.72). More patients with high TS staining tumors relapsed compared to those with low TS staining (p=0.01). Conclusions: Although we did not find a significant relationship between TS, cox-2 and overall survival, statistically significant RFS rates are suggestive of a correlation if these markers are studied in a greater sample size. No significant financial relationships to disclose.