Stage 3 EGFR-mutant lung cancer: osimertinib response to surgery

What happened, in summary

This 54-year-old woman was admitted after a left upper-lung nodule had been found 2 months earlier. Chest CT showed a 2.5 × 2.1 cm soft-tissue mass in the left upper-lung apex, and PET-CT showed metabolic activity in the left upper-lobe lesion and lymph nodes in the left hilum and mediastinum. Brain MRI and ultrasound of the abdomen, neck, and supraclavicular nodes did not show distant metastasis. Endobronchial ultrasound-guided biopsy of a 4L mediastinal lymph node confirmed lung adenocarcinoma with an EGFR exon 19 deletion. PD-L1 tumor proportion score was 1% or lower. The cancer was staged cT1cN2M0, Stage IIIA. Preoperative evaluation also found acute sick sinus syndrome, so a permanent cardiac pacemaker was implanted before cancer treatment. Because chemotherapy posed added cardiac risk and the tumor had an EGFR driver mutation, the multidisciplinary team chose neoadjuvant targeted therapy. She started osimertinib 80 mg once daily. After 6 weeks, CT showed partial response, with the primary lung tumor and involved lymph nodes all smaller. She then underwent single-port thoracoscopic left upper lobectomy with mediastinal lymphadenectomy. Surgery achieved R0 resection. Postoperative pathology showed ypT1bN2M0 Stage IIIA disease, about 20% viable residual tumor, and no lymphovascular invasion. She continued adjuvant osimertinib afterward. At follow-up, no recurrence or metastasis was reported, side effects were mild, and she was able to carry out daily work and social life. Her treatment also avoided the cardiotoxicity concern that had made standard neoadjuvant chemotherapy less attractive after pacemaker placement and cardiac evaluation. The response made surgery technically feasible.