[Precise therapy for lung cancer patients with rare sensitive mutations of epidermal growth factor receptor]

Precise medicine is an emerging clinical therapeutic concept based on genomic and genetic information of patients. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) is an important component of precise therapy for lung cancer patients. EGFR mutations occur mainly in exon 18 to 21, in which exon 19 deletion and exon 21 L858R point mutation that are known as sensitive mutations account for nearly 45% and 40%, respectively. Except for the above two mutations and T790M point mutation, the rest are rare mutations, including Ins19, Ins20, E709, G719, S768, L861 and some compound mutations. Some previous retrospective studies of small sample size and case reports showed that most of EGFR exon19 (Ins), exon 21 (L861), exon 18 (G719X) and exon20 (S768I) mutations were sensitive to TKIs. And although the exon 20 insertion mutation is usually predicted to the first and second generations of EGFR-TKIs resistance, some specific types are sensitive to the third generation of EGFR-TKIs. Currently, targeted drugs for Ins20 -Ap32788 mutation has entered into clinical trials. Patients with complex mutations have similar efficacy on EGFR-TKIs in comparison with those with single sensitivity mutations. In conclusion, when patients with rare sensitive mutations received EGFR-TKIs therapy, the efficacy and progression-free survival time is similar to or slightly lower than those with classical sensitive mutations, whereas it is higher than those with wild-type EGFR. Compared with the first generation of EGFR-TKIs, second generation EGFR-TKIs may be more suitable for the treatment of lung cancer patients harboring rare sensitive EGFR mutations.