Targeted therapy combined with local consolidative surgery for oligometastatic stage IVA lung adenocarcinoma with CCDC6-RET fusion: a case report.

Background: Precision therapy for non-small cell lung cancer (NSCLC) has expanded to include rare driver genes. RET fusion is a rare target in lung cancer, and data on targeted therapy combined with local consolidation surgery in advanced patients with oligometastatic status are limited. This article reports a case of successful surgical resection following initial systemic treatment with selpercatinib. Case presentation: A 68-year-old never-smoking male was diagnosed with adenocarcinoma of the right upper lobe (cT3N3M1, stage IVA) with ipsilateral pulmonary metastasis and cervical and axillary lymph node metastases, consistent with oligometastatic features. A CCDC6-RET fusion was identified via next-generation sequencing. The patient received selpercatinib for three months as initial systemic therapy. Results: Post-treatment imaging assessment indicated a partial response. The patient subsequently underwent successful thoracoscopic anterior segmentectomy of the right upper lobe with lymph node dissection. Postoperative pathology confirmed 15% residual viable tumor cells, which did not achieve major pathological response (MPR). Due to marked shrinkage and scar-like changes in the originally enlarged lymph nodes after targeted therapy, limited lymph node dissection was performed intraoperatively, and all submitted lymph nodes were negative. The postoperative pathological stage was ypT1aN0M0. Adjuvant selpercatinib was continued postoperatively, with no signs of recurrence during 7 months of follow-up. Conclusion: This case demonstrates that for selected patients with advanced lung adenocarcinoma harboring a CCDC6-RET fusion and oligometastatic disease, initial systemic therapy with selpercatinib followed by local consolidative surgery is a feasible multimodal strategy. This is not a routine recommendation for stage IV lung cancer but requires individualized decision-making after multidisciplinary discussion in specific oligometastatic cases.