Complete Response of Bone Metastasis in Non-small Cell Lung Cancer With Pembrolizumab: Two Case Reports

Aim To report two cases in which treatment with pembrolizumab for advanced non-small cell lung cancer (NSCLC) with bone metastasis of the long bone of the lower extremity in a state of impending fracture significantly ameliorated both lung tumor and bone metastasis. Case report Case 1 was a 74-year-old woman diagnosed with metastasis of NSCLC in the left tibia and case 2 was a 71-year-old man diagnosed with metastasis of NSCLC in the right femur; their bone metastases were in a state of impending fracture. Disease in both cases was already in stage IVB and they received systemic therapy using pembrolizumab, whilst the bone metastases were treated conservatively. After 3 months, both patients showed a complete response with remarkable osteosclerotic changes in bone metastases and the size of lung tumors was reduced. Conclusion These results might imply a novel strategy for systemic treatment with pembrolizumab is required, even in case of impending fracture in advanced NSCLC.