Cyclooxygenase-2 (COX-2) is an enzyme involved in prostaglandin production in pathologic states such as inflammatory processes and cancer. The enzyme is often overexpressed in premalignant lesions and cancer, including cancers of the lung and esophagus. Inhibition of this enzyme with selective COX-2 inhibitors was found to enhance tumor response to radiation in preclinical studies, suggesting that these agents can improve the response of various cancers to radiotherapy. On the basis of these preclinical findings, clinical trials of the combination of celecoxib, a selective COX-2 inhibitor, with radiotherapy were initiated in patients with lung carcinoma and with chemoradiotherapy in patients with esophageal carcinoma. The rationale for using selective COX-2 inhibitors is discussed, and the current clinical protocols and the initial findings are described.
From the Division of Radiation Oncology (Z.L., C.S., J.D.C.) and Department of Experimental Radiation Oncology (L.M.), The University of Texas M. D. Anderson Cancer Center, Houston, Texas, U.S.A.
This work was supported in part by the University of Texas M.D. Anderson Cancer Center, Department of Radiation Oncology funds, and a Seed Grant from the Research and Education Foundation of the Radiological Society of North America.
Address correspondence and reprints requests to Dr. Zhongxing Liao, Division of Radiation Oncology, Box 97, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, U.S.A.; e-mail: firstname.lastname@example.org