Abstract
BACKGROUND: EGFR and ALK alternations often contribute to human malignancies, including lung cancer. EGFR and ALK mutations are usually sensitive to EGFR-tyrosine kinase inhibitors (TKIs) and ALK-TKIs. Although generally mutually exclusive, these mutations do co-exist in rare cases. This study investigated the frequencies, clinical characteristics, therapeutic efficacies, and genetic profiles of lung cancer patients with EGFR and ALK co-mutations. METHODS: Patients with concurrent EGFR and ALK mutations were included in this study, which analyzed mutation profiles and treatment histories. SPSS20.0 were used for survival analysis. RESULTS: Among 271 ALK-positive (ALK-pos) and 2975 EGFR-positive (EGFR-pos) patients in our database, nine (2.6% of ALK-pos and 0.2% of EGFR-pos) patients had concurrent EGFR and ALK mutations (including three exon19 Indel + EML4-ALK, two exon19 Indel + STRN-ALK, two L858R + L1152R, one L858R + EML4-ALK, and one G719C + S768I + STRN-ALK). Eight patients had at least one type of EGFR-TKIs treatment. The median progression free survival (PFS) of these patients on first-generation EGFR-TKIs was 14.5 months (95% CI: 11 - NR). Of these eight patients, one who progressed on Gefitinib and subsequently on Osimertinib had a T790M + C797G. The other seven EGFR-TKIs resistance patients had no known resistance mutations. No patients had ALK mutations before treatment, so ALK mutations may have developed as resistance mechanisms during EGFR-TKIs therapies. EGFR-TKIs-treated patients with EGFR/ALK L1152R mutations generally had a shorter PFS than patients with other mutation combinations. CONCLUSIONS: ALK and EGFR mutations coincide at a relatively low frequency in lung cancer patients. ALK mutations developed either synchronously or heterochronously with EGFR mutations. Two ALK mutations (L1152R and STRN-ALK) may co-exist with EGFR mutations at a higher frequency than others. Most EGFR/ALK co-alteration patients (other than the EGFR/ALK L1152R type) can benefit from first line EGFR-TKIs.