PURPOSE: To determine the utility of COX-2 expression as a response predictor for patients with rectal cancer who are undergoing neoadjuvant radiochemotherapy (RCT). METHODS AND MATERIALS: Pretreatment biopsies (PTB) from 49 patients who underwent RCT were included. COX-2 and proliferation in PTB were assessed by immunohistochemistry (IHC) and apoptosis was detected by TUNEL stain. Response to treatment was assessed by a 5-point tumor-regression grade (TRG) based on the ratio of residual tumor to fibrosis. RESULTS: Good response (TRG 1+2), moderate response (TRG 3), and poor response (TRG 4+5) were seen in 21 patients (42%), 11 patients (22%), and 17 patients (34%), respectively. Patients with COX-2 overexpression in PTB were more likely to demonstrate moderate or poor response (TRG 3+4) to treatment than were those with normal COX-2 expression (p=0.026, chi-square test). Similarly, poor response was more likely if patients had low levels of spontaneous apoptosis in PTBs (p=0.0007, chi-square test). CONCLUSIONS: COX-2 overexpression and reduced apoptosis in PTB can predict poor response of rectal cancer to RCT. As COX-2 inhibitors are commercially available, their administration to patients who overexpress COX-2 warrants assessment in clinical trials in an attempt to increase overall response rates.
PURPOSE: To determine the utility of COX-2 expression as a response predictor for patients with rectal cancer who are undergoing neoadjuvant radiochemotherapy (RCT). METHODS AND MATERIALS: Pretreatment biopsies (PTB) from 49 patients who underwent RCT were included. COX-2 and proliferation in PTB were assessed by immunohistochemistry (IHC) and apoptosis was detected by TUNEL stain. Response to treatment was assessed by a 5-point tumor-regression grade (TRG) based on the ratio of residual tumor to fibrosis. RESULTS: Good response (TRG 1+2), moderate response (TRG 3), and poor response (TRG 4+5) were seen in 21 patients (42%), 11 patients (22%), and 17 patients (34%), respectively. Patients with COX-2 overexpression in PTB were more likely to demonstrate moderate or poor response (TRG 3+4) to treatment than were those with normal COX-2 expression (p=0.026, chi-square test). Similarly, poor response was more likely if patients had low levels of spontaneous apoptosis in PTBs (p=0.0007, chi-square test). CONCLUSIONS:COX-2 overexpression and reduced apoptosis in PTB can predict poor response of rectal cancer to RCT. As COX-2 inhibitors are commercially available, their administration to patients who overexpress COX-2 warrants assessment in clinical trials in an attempt to increase overall response rates.
Authors: Li-Yan Khor; Kyounghwa Bae; Alan Pollack; M Elizabeth H Hammond; David J Grignon; Varagur M Venkatesan; Seth A Rosenthal; Mark A Ritter; Howard M Sandler; Gerald E Hanks; William U Shipley; Adam P Dicker Journal: Lancet Oncol Date: 2007-09-18 Impact factor: 41.316