Purpose: To evaluate seven molecular markers including cyclooxygenase -2, epidermal growth factor receptor, Ki-67, p21, survivin, thymidylate synthase, and vascular endothelial growth factor for prediction of response to preoperative chemoradiotherapy in locally advanced rectal cancer.
Materials and methods: Fifty-four patients with clinical T3-4 and/or node-positive rectal cancer who underwent preoperative chemoradiotherapy followed by surgical resection were enrolled into this study. Preoperative chemoradiotherapy consisted of 50.4 Gy of pelvic irradiation with concomitant 5-fluorouracil or oral capecitabine. Expression of molecular markers in pretreatment paraffin-embedded tumor biopsy specimens was assessed by immunohistochemical staining on the tissue microarray. Tumor downstaging was used as an endpoint for evaluation of tumor response.
Results: Tumor downstaging was observed in 22 patients (41%), and pathologic complete remission in 7 patients (13%). Among seven molecular markers, only survivin expression was significantly related with tumor downstaging: 26% with high survivin expression (>75% in extent) vs. 72% with low survivin expression (p = 0.0011). However, other six molecular markers were found not to have any correlation with tumor downstaging.
Conclusions: High survivin expression in pretreatment tumor biopsy was associated with less tumor downstaging after preoperative chemoradiotherapy for locally advanced rectal cancer.