Background: Neoadjuvant chemoradiotherapy followed by total mesorectal excision is the standard therapy for localized rectal adenocarcinoma. Neoadjuvant chemoradiation has been shown to increase local control and facilitate surgery. In 
this trial, we aimed to assess the impact of celecoxib in addition to neoadjuvant chemoradiation on pathologic response 
rates and treatment-related toxicity in locally advanced rectal adenocarcinoma.
Patients and Methods: Total 30 patients were enrolled in this phase 2 study. Patients underwent full colonoscopy + 
baseline scans and then received neoadjuvant therapy (capecitabine 825 mg/m2  bid in combination with celecoxib 200 mg bid and radiotherapy (50–50.4 Gy/25–28 fraction, 5 fractions/week). Surgery was done 8–12 weeks after chemoradiation. Acute complications were scored by common toxicity criteria 5.0.
Results: Of 30 patients, total mesorectal excision was done in 22 patients. Tumor regression grade was reported as: seven (31.8%) patients had grade 0 or complete response, seven (31.8%) patients had grade 1 or moderate response, six (27%) 
patients had grade 2 or minimal response and two (9%) patients had grade 3 or poor response. No patients had acute 
hematologic or cardio-vascular toxicity.
Conclusion: Results indicate that adding celecoxib to neoadjuvant therapy for rectal adenocarcinoma can promote 
pathologic complete response and decrease acute therapy toxicity.