Abstract
RATIONALE: The targeting of signal transduction through programmed cell death receptor-1 (PD-1) and its ligand programmed cell death-ligand 1 (PD-L1) in patients with non-small cell lung cancer (NSCLC) has been widely applied in clinical research. However, the subtypes and treatment patterns that predict responses to PD-1/PD-L1 inhibitors are not fully understood. Biomarkers, such as PD-L1 expression, tumor mutation load, and DNA mismatch repair defects, have been used to screen patients who respond to PD-1/PD-L1 inhibitors, but the appropriate treatment mode requires further investigation. Immune checkpoint inhibitors combined with radiotherapy provide benefits from remote effects, especially in NSCLC patients with increased PD-L1 expression. PATIENT CONCERNS: We report a 64-year-old man who presented with left back pain for 40 days. A computed tomography scan showed a mass in the right upper lobe of the lung, with metastases in the right hilar and mediastinal lymph nodes. DIAGNOSIS: NSCLC-not otherwise specified was diagnosed by computed tomography-guided lung biopsy. INTERVENTIONS: After the failure of first-line chemotherapy, next-generation sequencing was performed for comprehensive gene analysis, and PD-L1 expression levels were evaluated by immunohistochemistry. The patient was treated with toripalimab (a PD-1 inhibitor) concurrently with radiotherapy for bone metastases. OUTCOMES: The detection results showed a high tumor mutation burden and increased PD-L1 expression. On the basis of these findings, the patient received toripalimab (PD-1 inhibitor) combined with radiotherapy for bone metastases. Partial response was achieved after 3 cycles, and the patient showed stable disease at the end of the sixth and ninth cycles of toripalimab. The patient was followed up for 26 months. At present, the patient is receiving toripalimab maintenance treatment, which has been well-tolerated without adverse events. LESSON: Toripalimab combined with radiotherapy may exert a synergistic anti-tumor effect through remote effects in advanced or metastatic NSCLC with high PD-L1 expression. However, the specific treatment mode requires further confirmation by the investigation of additional cases.