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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Apoptosis, Biomarkers, Tumor, Biopsy, Cyclooxygenase 2, Female, Humans, In Situ Nick-End Labeling, Ki-67 Antigen, Male, Neoadjuvant Therapy, Neoplasm Staging, Rectal Neoplasms, Rectum, Treatment Outcome.
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Does cOX-2 overexpression in pretreatment biopsies predict response of rectal cancers to neoadjuvant radiochemotherapy? Context: To determine the utility of COX-2 expression as a response predictor for patients with rectal cancer who are undergoing neoadjuvant radiochemotherapy (RCT). 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. 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).
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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. Final Decision: yes