Thymidylate Synthase Expression and Prognosis in Colorectal Cancer: A Meta-Analysis of Colorectal Cancer Survival Data

Abstract

Background Although many studies have investigated the prognostic effect of thymidylate synthase (TS) in colorectal cancer, no consensus has been reached. The aim of this meta-analysis was to obtain a more precise estimate of the prognostic significance of TS expression in localized cancers treated by curative resection and adjuvant chemotherapy. Materials and method Seventeen eligible studies reporting survival in 2,893 patients stratified by TS expression were pooled using a fixed- or random-effects model. The main outcome measure was hazard ratio (HR). Results The overall HR for overall survival was 1.01 (95% CI 0.74–1.39, p=0.947), with an I2 of 64.4%. The total HR for disease-free survival was 1.36 (95% CI 0.97–1.89, p=0.072), with an I2 of 75.8%. In the TS protein-tested subgroup, the total HR for disease-free survival was 1.72 (95% CI 1.02–2.89, p=0.042), with an I2 of 81.3%. Conclusion Our meta-analysis showed that, in the adjuvant setting, TS expression does not predict a poorer disease-free survival or a worse overall survival. Therefore, we believe that it is inappropriate to regard TS expression as a prognostic factor for patients with stage II and stage III colorectal cancer treated by surgery and adjuvant chemotherapy.