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.