EGFR TKI Combined with PD1 Inhibitor for EGFR Mutated Lung Cancer with Breast Metastasis

Background: Lung adenocarcinoma with breast metastasis is rare. In the present study, a case of an advanced patient with breast metastasis from lung adenocarcinoma with EGFR 21 exon p.L858R mutation who underwent EGFR TKI combined with PD1 inhibitor is reported. Case presentation A 62-year-old female patient diagnosed with lung adenocarcinoma who had undergone six times disease progress and breast metastasis in fifth-time disease progress.The patient underwent left breast puncture and axillary lymph node in ultrasound-guided and the postoperative pathological diagnosis of metastatic lung adenocarcinoma was confirmed. And then gene detection showed EGFR 21 exon p.L858R mutation. Breast metastasis from lung adenocarcinoma was diagnosed and the patient is being treated with Almonertinib combined with PD1 inhibitor. Conclusion: Breast metastasis is rare and lung adenocarcinoma might be the primary disease. Gene indection is important. And for lung cancer patients with recurrent pleural effusion, visit of the breast should be included in the follow-up process. In addition, the treatment model of interspersed immunotherapy after EGFR resistance has brought new ideas for the treatment of lung cancer with breast metastasis.