Importance of thymidine phosphorylase, dihydropyrimidine dehydrogenase and thymidylate synthase expression at the invasive front of T3 rectal cancer as prognostic factors.

Background/aims: We evaluated a relationship between postoperative recurrence and thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD) and thymidylate synthase (TS) expression at the invasive front of T3 rectal cancer.

Methodology: This study was conducted on 61 patients with T3 rectal cancer who underwent surgically curative resection between 1998 and 2002. Paraffin-embedded sections of these patients were immunostained for TP, DPD and TS. Relationship between expression level of the three factors and postoperative recurrence were evaluated.

Results: There was no relationship between expression of DPD or TS in the tumor cells and recurrences. Although no relationship was present between expression of TP in the stromal cells around the invasive front of the tumor and postoperative recurrences, there was a strong correlation between expression of TP in the invasive front of the tumor and postoperative recurrence. Moreover, by multivariate logistic regression analysis, TP expression in the tumor cells was the only independent contributory factor for postoperative recurrences (p = 0.021) with an odds ratio of 8.27.

Conclusions: TP expression at the invasive front of the tumor may be an important prognostic factor for T3 rectal cancer, and patients with such a condition may benefit from intensive chemotherapy.