Long-term survival after stereotactic body radiotherapy combined with immunotherapy plus anti-angiogenesis therapy in patients with advanced non-small cell lung cancer and EGFR exon 20 insertion mutation: a report of two cases

Background: Epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutation is the third most common EGFR-mutant form, accounting for 10-12% of all EGFR mutations in non-small cell lung cancer (NSCLC). Chemotherapy was the first-line treatment for patients with EGFR ex20ins mutation in the era when EGFR ex20ins tyrosine kinase inhibitors (EGFR ex20ins-TKIs) were inaccessible. Although EGFR ex20ins-TKIs have since then demonstrated certain efficacy, the population benefit rate is not high due to the high cost of the drug and limited benefit to the population. Therefore, the choice of treatment modality when a patient does not have access to EGFR ex20ins-TKIs or are resistant to them remains an avenue worth exploring. Case Description: In this report, we present two cases of patients with lung adenocarcinoma and EGFR ex20ins mutation. The two patients were middle-aged Asian women with no smoking history, and both had one or more metastatic lesions. Both achieved long-term clinical benefit (progression-free survival >= 12 months) after receiving combined treatment, suggesting that this is a promising treatment modality. Conclusions: To the best of our knowledge, this is the first report supporting the combination of stereotactic body radiotherapy and apatinib and camrelizumab as an effective treatment strategy in patients with advanced EGFR ex20ins-positive NSCLC who have been previously treated with chemotherapy. The therapy described in this report might serve as a potential alternative approach for clinical oncologists. Keywords: Epidermal growth factor receptor exon 20 insertion mutation (EGFR ex20ins mutation); stereotactic