Objective: To evaluate the effect of pemetrexed plus platinum for chemotherapy-naive advanced non-small cell lung cancer (NSCLC), and to explore thymidylate synthetase (TS) expression as the predictive and prognostic factor for this treatment.
Methods: This retrospective study enrolled 51 patients with chemotherapy-naive advanced NSCLC (non-squamous) treated at Department of Thoracic Medical Oncology in Beijing Cancer Hospital from Jan 2008 to Oct 2009. All patients received pemetrexed plus platinum as first-line treatment. TS expression was detected in 30 patients who had enough tissue samples by immunohistochemistry.
Results: The objective response rate (ORR) was 37.3%. Median progression-free survival (PFS) was 5.3 months (95%CI: 3.9 - 6.7), and median overall survival (OS) was 19.0 months (95%CI: 11.6 - 26.4). Univariate analysis showed that gender, pathology, smoking status and response were significantly correlated with OS. Cox-regression analysis showed that pathology was an independent prognostic factor. Rate of Grade 3/4 adverse events was low. In 30 patients with enough tissue samples were available, TS expression positive rate was 33.3% (10/30). Chi-square test showed that TS expression was not associated with ORR. Multivariate analysis showed that pathology, response and TS expression (P = 0.003, 0.005 and 0.001, respectively) were the prognostic factors.
Conclusion: The therapeutic effect and tolerance of pemetrexed plus platinum regiment were definite as first-line treatment for chemotherapy-naive advanced NSCLC, and TS expression was an independent prognostic factor.