Has Cox-2 a prognostic role in non-small-cell lung cancer? A systematic review of the literature with meta-analysis of the survival results

Cyclooxygenase-2 (COX- 2) is overexpressed in lung cancer, especially in adenocarcinoma ( ADC). Our aim was to determine the prognostic value of COX- 2 on survival in patients with lung cancer. Studies evaluating the survival impact of COX- 2 in lung cancer, published until December 2005, were selected. Data for estimation of individual hazard ratios ( HR) for survival were extracted from the publications and combined in a pooled HR. Among 14 eligible papers, all dealing with non- small- cell lung cancer, 10 provided results for meta- analysis of survival data ( evaluable studies). Cyclooxygenase- 2 positivity was associated with reduced survival, improved survival or no statistically significant impact in six, one and seven studies, respectively. Combined HR for the 10 evaluable studies ( 1236 patients) was 1.39 ( 95% confidence intervals ( CI): 0.97 - 1.99). In stage I lung cancer ( six evaluable studies, 554 patients), it was 1.64 ( 95% CI: 1.21 - 2.24). No significant impact was shown in ADC. A slight detrimental effect on survival in patients with lung cancer is associated with COX- 2 expression, but the statistical significance is not reached. This effect is statistically significant in stage I, suggesting that COX- 2 expression could be useful at early stages to distinguish those with a worse prognosis.