Comparison of erlotinib and pemetrexed as second-/third-line treatment for lung adenocarcinoma patients with asymptomatic brain metastases

Objective: Brain metastases occur in one-third of all non-small-cell lung cancer patients. Due to restrictive transport at the blood-brain barrier, many drugs provide poor control of metastases in the brain. The aim of this study was to compare erlotinib with pemetrexed as second-/third-line treatment in patients with lung adenocarcinoma with asymptomatic brain metastases. Methods: From January 2012 to June 2014, all lung adenocarcinoma patients with asymptomatic brain metastases who received treatment with erlotinib or pemetrexed as second-/third-line treatment were retrospectively reviewed. Chi-square and log-rank tests were used to perform statistical analysis. Results: The study enrolled 99 patients, of which 44 were positive for EGFR mutation. Median progression-free survival (PFS) in months was not significantly different between the erlotinib- and pemetrexed-treated groups (4.2 vs 3.4 months; 95% confidence interval [CI]: 2.01-6.40 vs 2.80-5.00, respectively; P=0.635). Median PFS was found to be significantly longer in EGFR mutation-positive patients in the erlotinib-treated group (8.0 months; 95% CI 5.85-10.15) compared to the pemetrexed group (3.9 months; 95% CI: 1.25-6.55; P=0.032). The most common treatment-related side effect was mild-to-moderate rash and the most common drug-related side effects in the pemetrexed-group were vomiting and nausea. Conclusion: Erlotinib and pemetrexed may be used as second-/third-line treatment in lung adenocarcinoma patients with asymptomatic brain metastases, and detection of EGFR mutation status is very important in these patients. EGFR mutation-positive lung adenocarcinoma patients with asymptomatic brain metastases showed longer PFS when treated with erlotinib as opposed to pemetrexed.