Eastern Section Program

OBJECTIVES: The purpose of this analysis is to elucidate a relationship between cyclooxygenase-2 (COX-2) expression and local relapse in a large cohort of patients with T12N0 larynx cancer treated with primary radiation therapy. STUDY DESIGN: Please see Methods. METHODS: Clinical and molecular analyses were conducted on 123 patients with biopsy-proven T1-2N0 larynx cancer. Clinical prognostic factors included pretreatment hemoglobin level, age, sex, race, T stage, tumor subsite, beam energy, biologically equivalent dosage, and therapy duration. Molecular prognostic factors included COX-2, p53, and Ki-67 expression. Expression levels were determined by immunohistochemistry on paraffin-embedded tissues arrayed on tissue microarrays. Multivariate analysis was done with the Cox proportional hazards model. RESULTS: Thirty-two patients have locally relapsed for an actuarial 5-year local relapse-free rate of 70.4%. On multivariate analysis, positive COX-2 expression predicted for local relapse after radiation therapy. The relative risk (RR) for local relapse with COX-2 positivity was 2.57 (95% confidence interval [CI] 1.21-5.47) (P=0.01). Other prognostic factors for local relapse included negative Ki-67 expression (RR=5.72 [CI] 2.04-16.1) (P<0.001), T2 stage (RR=2.98 [CI] 1.39-6.38) (P=0.005), and therapy duration greater than 43