What happened, in summary

A 58-year-old man with a long smoking history was diagnosed with lung adenocarcinoma in the right lower lobe. He underwent right lower lobectomy with mediastinal lymph-node dissection in March 2021. Pathology showed Stage III disease with spread to several regional lymph nodes.

Tumor testing identified a rare KIF13A-RET fusion. He declined postoperative chemotherapy and instead started pralsetinib about three months after surgery. Circulating tumor DNA remained undetectable during early follow-up, although his medication use later became irregular.

After about 27 months without recurrence, testing and imaging began to show recurrent disease. A right pleural lesion enlarged and mediastinal nodes progressed, representing metastatic recurrence. He continued pralsetinib and bevacizumab was added. Two months later, imaging showed reduction in the pleural lesion and mediastinal lymph nodes, and circulating tumor DNA became undetectable again by December 2023.