Cyclooxygenase-2 expression is a prognostic biomarker for non-small cell lung cancer patients treated with adjuvant platinum-based chemotherapy.

Background: Adjuvant chemotherapy after the resection of stage IB-IIIA non-small cell lung cancer (NSCLC) is now the standard of care based on large-scale phase III trials and a meta-analysis. However, chemotherapy has plateaued in terms of its efficacy, and the search for treatment prediction biomarkers is imperative for the further identification of treatable subgroups. Therefore, we investigated the significance of cyclooxygenase-2 (Cox-2) expression and the applicability of a Cox-2 inhibitor in patients who had received adjuvant chemotherapy.
Methods: We conducted a retrospective review of data from 97 patients who had received adjuvant chemotherapy. The adjuvant chemotherapy consisted of an oral tegafur agent (OT) or platinum-based chemotherapy (PB). The criteria for regimen selection were based on a discussion among the cancer board and enrollment in a clinical trial. Immunohistochemical staining (IHC) for Cox-2 was performed, and the correlation between Cox-2 expression and disease-free survival (DFS) was evaluated.
Results: IHC showed that 56 cases (57.7%) were positive for Cox-2. The rate of Cox-2 expression was similar for the PB and OT groups. Among the patients who received PB, the DFS of the patients with Cox-2 expression was significantly poorer than that of the patients without Cox-2 expression (P = 0.017), but there was no significant difference among the patients who received OT (P = 0.617). In a multivariate analysis, Cox-2 expression and lymph node metastasis were independent predictors of DFS among patients who received PB.
Conclusions: Cox-2 expression was a powerful predictor of DFS among patients who received PB as an adjuvant chemotherapy. Further study investigating the use of a Cox-2 inhibitor for adjuvant chemotherapy is needed.