The expression of epidermal growth factor receptor results in a worse prognosis for patients with rectal cancer treated with preoperative radiotherapy: a multicenter, retrospective analysis.

BACKGROUND AND PURPOSE: Expression of epidermal growth factor receptor (EGFR) is observed in 50-70% of colorectal carcinoma and is associated with poor prognosis. The aim of this study was to determine the prognostic value of EGFR status before radiotherapy in a group of patients with locally advanced rectal cancer treated with preoperative radiotherapy. PATIENTS AND METHODS: Eighty-seven patients were studied retrospectively. Treatment consisted of pelvic radiotherapy, in 50 patients with concomitant chemotherapy and surgical resection. Immunohistochemistry for EGFR was determined at the preradiation biopsy and in the resected specimens. Immunohistochemical analysis for EGFR expression was evaluated according to extension and staining intensity. We defined positive staining (EGFR positive), when extension was 5% or more. RESULTS: A total of 52 of 87 tumors showed EGFR positive status at biopsy (60%) and EGFR expression was associated neither with clinical tumor stage nor with clinical nodal stage. EGFR positive expression was linked to a lack of pathologic complete response to preoperative radiotherapy (P=0.006). Disease-free survival was lower among patients with EGFR positive status before radiotherapy (P=0.003). In a multivariate analysis EGFR expression at biopsy was a statistically significant predictor of disease-free survival, RR=2.88(1.1-7.8), P=0.036. CONCLUSIONS: EGFR is expressed in a significant number of rectal tumors. EGFR-positive expression before radiotherapy is an indicator for poor response and low disease-free survival.

Epidermal growth factor receptor is a predictor of tumor response in locally advanced rectal cancer patients treated with preoperative radiotherapy.

PURPOSE: Epidermal growth factor receptor (EGFR) expression is observed in 50%-70% of colorectal carcinomas and is associated with poor prognosis. The aim of this study was to determine the EGFR expression rate in locally advanced rectal cancer and to analyze whether EGFR expression predicts tumor response to preoperative radiotherapy. METHODS AND MATERIALS: Between December 1997 and October 2000, 45 patients were included. Treatment consisted of preoperative pelvic radiotherapy and, in 21 patients, 2 courses of 5-fluorouracil leucovorin. Surgical resection was performed 4-8 weeks later. Immunohistochemistry for EGFR was determined at the preradiation diagnostic biopsy and in the resected specimens. Immunostaining was performed using EGFR monoclonal antibody (Biogenex, MU 207-UC). Immunohistochemical staining was evaluated according to extension and intensity. We defined positive staining (EGFR+) as extension of 5% or more. RESULTS: Preoperative treatment resulted in pathologic complete remission in 7 patients (15%), downstaging in 13 patients (29%), and no response in 25 patients (56%). EGFR+ was observed in 29 of 45 tumors (64%) and was associated with neither clinical tumor stage nor clinical nodal stage. The overall response rate was 34% in EGFR+ patients vs. 62% in those who were EGFR- (p = 0.07). Only 1 of the 7 pathologic complete remission patients was EGFR+ (p = 0.003). CONCLUSIONS: EGFR is expressed in a significant number of locally advanced rectal tumors. EGFR expression is an indicator for poor response to preoperative radiotherapy in advanced rectal carcinoma.