Effect of clinical parameters on second- and third-line erlotinib treatment of EGFR wild type patients with advanced NSCLC
Abstract
Introduction: Elotinib treatment in patients without EGFR-sensitive mutations (NSCLC) is only successful in a minority of patients. Therefore, there is an attempt to find possible predictive markers to determine the efficacy of erlotinib in these patients.
The aim of our study is to assess the effect of clinical parameters on progression free survival (PFS) and overall survival (OS) on the efficacy of erlotinib treatment in this patients' group. Patients and Methods: In our retrospective work from (pneumo-)oncology centers in the Czech Republic, we evaluated the records in 2700 patients from the TULUNG registry who did not have an EGFR mutation and were treated with erlotinib in second / third line treatment for advanced NSCLC.
The influence of age (under/above 65 years), gender, performance status (ECOG PS), smoking (ex-/smokers vs. non-smokers), disease stages (IIIB vs. IV), histology (adenocarcinoma vs. squamous carcinoma vs. others), EGFR status (negative vs. unknown) and the erlotinib treatment line (second vs. third line treatment) on PFS and OS were evaluated.
For the univariate analysis, Kaplan-Meir curves and log-rank test were used. Furthermore, a multivariate analysis using the Cox model was calculated.
As a level of statistical significance, α = 0.05 was used. Results: In the multivariate analysis, the stage of disease, ECOG PS and gender of the patients were significant factors for OS and all examined parameters had significant effect on PFS except for NSCLC histology.
The treatment line has not already a significant effect on PFS and OS in univariate analysis. Conclusion: Due to the meta-analysis showing better PFS-administered chemotherapy in the second line treatment of EGFR-wt patients in comparison with erlotinib treatment, our important finding is that the administration of erlotinib in third line does not affect PFS.
Some selected groups of patients may probably benefit more from this treatment, but our conclusions may be influenced by a considerable group of patients without known EGFR status. Overall, the patients ECOG PS >= 2 are the only clinical group in which the third line treatment of erlotinib appears to be unsuitable due to very low PFS.