Molecular Prognostic Factors in Locally Irresectable Rectal Cancer Treated Preoperatively by Chemo-radiotherapy

Abstract

Purpose: The aim of this study was to determine the relationship between survival and value of molecular markers in the primary tumour in a group of patients with irresectable rectal cancer, treated with preoperative chemoradiotherapy. Materials and Methods: Immunohistochemistry for p53, p21, bcl-2 and Ki-67 was performed on pre-treatment biopsy specimens of 34 patients with irresectable rectal cancer. Preoperative treatment consisted of pelvic irradiation of 45-56 Gy, combined with 5FU and leucovorin (350/20 mg/m² x 5 d; in weeks 1 and 5 during radiotherapy). The median follow-up was 38 months. Endpoints were pathological T-stage and survival after surgery. Results: Expression of p21 correlated significantly with survival (p=0.005). Survival and p21 expression also correlated significantly, when adjusted for tumour response (p=0.005, RR=4.8 (1.6-14.7)). Conclusion: Expression of p21 predicts a worse survival in irresectable rectal cancer treated with preoperative chemo-radiotherapy. No relationship was found between tumour response in chemo-radiotherapy and p53, bcl-2 or Ki-67.