Clinical Outcomes and Prognostic Factors Associated with the Response to Erlotinib in Non-Small-Cell Lung Cancer Patients with Unknown EGFR Mutational Status

Background: The efficacy of erlotinib is controversial in patients with unknown EGFR mutational status.The aim of this study was to identify the clinicopathological factors that are predictive of erlotinob treatmentoutcomes for NSCLC patients with unknown EGFR mutational status. Materials and
Methods: A retrospectiveanalysis of 109 patients with advanced NSCLC who had previously failed at least one line of chemotherapy andreceived subsequent treatment with erlotinib (150 mg/day orally) was performed. A Cox proportional hazardmodel for univariate and multivariate analyses was used to identify the baseline clinical parameters correlatingwith treatment outcome, expressed in terms of hazard ratios (HRs) and 95% confidence intervals.
Results: Themedian treatment duration was 15 weeks (range, 4-184). The disease control rate was 55%, including diseasestability for ≥3 months for 40% of the patients. Median progression-free survival and median overall survival(OS) were 4.2 and 8.5 months, respectively. The Cox model indicated that an Eastern Cooperative OncologyGroup performance status (ECOG PS) ≥2 (HR 3.82; p<0.001), presence of intra-abdominal metastasis (HR 3.42;p=0.002), 2 or more prior chemotherapy regimens (HR 2.29; p=0.021), and weight loss >5% (HR 2.05; p=0.034)were independent adverse prognostic factors for OS in NSCLC patients treated with erlotinib.
Conclusions: Thisstudy suggests that NSCLC patients should be enrolled in erlotinib treatment after a first round of unsuccessfulchemotherapy to improve treatment success, during which they should be monitored for intra-abdominalmetastasis and weight loss.