A systematic review of the cyclooxygenase‐2 (Cox‐2) expression in rectal cancer patients treated with preoperative radiotherapy or radiochemotherapy

Abstract

The main objective of this systematic review is to investigate the expression level of the cyclooxygenase‐2 (COX‐2) in rectal cancer treated with either preoperative radiotherapy or radiochemotherapy. In addition, we have summarized the effects of preoperative treatment of rectal cancer with regards to the expression levels of COX‐2. A systematic literature review was performed in The Cochrane Library, PubMed, Web of Science, and Scopus databases on 1st January 2021 with the usage of the following search string—(cyclooxygenase‐2) OR (COX‐2) AND (rectal cancer) AND (preoperative radiochemotherapy) OR (preoperative radiotherapy). Among the 176 included in the analysis, only 13 studies were included for data extraction with a total number of 2095 patients. The results of the analysis are based on the articles concerning the expression of COX‐2 in rectal cancer among patients treated with preoperative radiotherapy or radiochemotherapy. A COX‐2 expression is an early event involved in rectal cancer development. In cases of negative COX‐2 expression, radiotherapy and radiochemotherapy might contribute to the reduction of a local recurrence. Therefore, COX‐2 may be considered as a biologic factor while selecting patients for more effective, less time‐consuming and less expensive preoperative treatment. However, the utility of the administration of COX‐2 inhibitors to patients with COX‐2 overexpression, in an attempt to improve the patients’ response rate to the neoadjuvant treatment, needs an assessment in further clinical trials.