Concurrent afatinib and stereotactic body radiotherapy in patient with oligometastatic EGFR-mutated non-small cell lung cancer: a case report and literature review.

Background: Epidermal growth factor receptor (EGFR)-mutated patients treated with target therapy are inevitable to develop resistance to tyrosine kinase inhibitors (TKIs). It has been proved that concurrent stereotactic body radiotherapy (SBRT) and the first-generation TKIs can prolong both progression-free survival (PFS) and overall survival (OS) of EGFR-mutated patients with limited metastases. However, the efficacy and safety of concomitant second-generation TKIs and SBRT is still unknown.

Case description: We for the first time present a stage IVA patient with mutation of both EGFR G719X and L861Q, who after initial response, had developed intracranial progression during afatinib monotherapy. With local treatment for the brain metastasis, she continued to receive afatinib and then a concurrent consolidative lung SBRT. Until January 2023, the patient had achieved a PFS of 24 months and OS of 32 months without serious adverse events except for a grade 1 radiation pneumonitis after the lung SBRT.

Conclusions: With this case and a literature review, we aim to demonstrate that concurrent afatinib and consolidative SBRT can bring prognostic benefits to oligometastatic NSCLC patients with uncommon EGFR mutations with good tolerance. However, larger studies with longer follow-up, including randomized controlled trials, are needed to better define the response rates, survival outcomes, and toxicity profiles of this combined therapy. Additionally, further research is required to determine the optimal timing for introducing SBRT in conjunction with afatinib.