Expression of cyclooxygenase (COX)-2 as a prognostic factor in nasopharyngeal cancer.

Purpose: To evaluate the relationship between treatment failure and COX-2 expression in nasopharyngeal cancer patients treated with chemotherapy and radiotherapy.

Materials And Methods: The subjects of this study were 22 nasopharyngeal cancer patients. The patients were treated with neoadjuvant chemotherapy, followed by radiotherapy, or with radiotherapy alone. The formalin-fixed, paraffin-embedded tissues of 11 patients who developed a locoregional recurrence (n=7) or distant metastasis (n=4) were compared with those of 11 disease free patients. Prognostic factors, including histological type, stage, radiation dose and chemotherapy, were well balanced between the two groups. The COX-2 expression was determined immunohistochemically.

Results: COX-2 expression was stronger in the patients with a locoregional recurrence or distant metastasis than in those free of disease. The COX-2 distribution scores of the control group were as follows: 0 in 7, 1 in 2 and 2 in 2 patients. In the recurrence group, the scores were as follows; 0 in 3, 1 in 1, 2 in 2 and 3 in 5 patients. COX-2 expression was shown to have a statistically significant influence on the treatment failure by the Mann-Whitney U test (p=0.024) and Mantel-Haenszel Chi-Square test (p=0.018). It also significantly influenced the treatment failure when an analysis was performed within patients with a undifferentiated histology (p=0.039 by the Mann-Whitney U test, p=0.037 by the Mantel-Haenszel Chi-Square test).

Conclusion: COX-2 expression is believed to be one of the important factors associated with a locoregional recurrence or distant metastasis.