Stage IV METex14 lung adenocarcinoma: responding well to capmatinib and SBRT

What happened, in summary

This 73-year-old man had well-controlled type 2 diabetes, a 25 pack-year smoking history, productive cough, coughing blood, 3 kg of weight loss, and worsening general health. Chest CT showed a large right upper-lobe lung mass measuring 9 x 7.5 x 5 cm, intertracheobronchial lymph nodes, and a lytic lesion in the D7 vertebral body. CT-guided biopsy confirmed moderately differentiated lung adenocarcinoma. Staging showed a small 3 mm enhancing brain focus and bone disease involving thoracic and lumbar vertebrae, with additional suspicious cervical and thoracic lesions. PET/CT also showed mediastinal lymph-node involvement. The cancer was diagnosed as oligometastatic lung adenocarcinoma with limited brain and bone involvement. Immunohistochemistry showed CK7-positive, CK20-positive, TTF-1-positive, P40-negative disease, with PD-L1 expression above 80%. Next-generation sequencing identified a MET exon 14 skipping mutation and no EGFR, RAS, or MEK alterations. A multidisciplinary tumor board recommended capmatinib 800 mg/day with denosumab. He first received SBRT to vertebral metastases, 30 Gy in 3 fractions, which quickly relieved pain. The asymptomatic brain lesion was not irradiated. After 3 months on capmatinib, PET/CT showed partial metabolic and volume regression of the primary lung cancer and resolution of bone hypermetabolism. At 10 months, imaging showed further tumor regression and complete resolution of mediastinal uptake, allowing SBRT to the primary lung lesion, 50 Gy in 5 fractions. Brain MRI later showed complete resolution of the enhancing lesion. At 18 months, isolated right iliac crest oligoprogression was treated with pelvic SBRT. At 24 months, he was alive, asymptomatic, still taking capmatinib, and had no evidence of disease progression.