A 78-year-old male with a smoking history of approximately 40 pack-years presented on April 25, 2018, with a two-month history of intermittent irritating cough, which had recently worsened over ten days and was accompanied by dysphagia, choking, and intermittent dull pain in the right scapular area. Self-administered traditional Chinese medicine and cephalosporin antibiotics provided no relief. A chest CT scan from an external facility revealed a mass near the right hilum and multiple bilateral nodules, suggestive of lung cancer with extensive intra-pulmonary and lymph node metastases. The patient’s medical history included 18 years of diabetes mellitus (controlled with metformin and glipizide), 5 years of hypertension (maximum 150/70 mmHg, controlled with bisoprolol), 18 years of lacunar cerebral infarction without significant sequelae, and 6 years of coronary heart disease status post coronary stent implantation, on long-term aspirin therapy.

The entire diagnostic and therapeutic journey is summarized in Figures 1 and 2, with serial CT images shown in Figure 3.

First, this case provides rare long-term real-world evidence of continuous remission exceeding seven years with nivolumab monotherapy in a patient with exceptionally high PD-L1 expression (TPS 90%), vividly illustrating the characteristic “tail effect” of immunotherapy. Second, the patient was 78 years old with multiple significant comorbidities (coronary heart disease, diabetes, hypertension), yet achieved excellent efficacy and tolerability, challenging conventional hesitations about using immunotherapy in such complex elderly patients and providing valuable management experience (5, 7). Finally, the complete series of CT images provides clear and compelling visual evidence of this dramatic therapeutic response.

This study is a retrospective case report with inherent limitations. First, we did not perform tumor mutational burden (TMB) testing, preventing a comprehensive analysis of its association with ultra-long survival. Second, as a retrospective analysis, our assessment of immune-related adverse events (irAEs) was based on medical records rather than prospective systematic scale evaluations. Most importantly, a single case report cannot provide mechanistic evidence for synergistic effects between sequential chemotherapy and immunotherapy. These limitations also point to directions for future prospective research.

The high response rate in this case strongly correlates with high PD-L1 expression, reaffirming PD-L1’s value as an important predictive biomarker (5, 8). Interestingly, the patient responded profoundly to subsequent immunotherapy despite progression after first-line chemotherapy. Some basic research suggests that chemotherapy may alter the tumor microenvironment by inducing immunogenic cell death, potentially creating favorable conditions for subsequent immunotherapy (9). However, it must be clearly stated that this case itself cannot provide direct mechanistic evidence supporting this hypothesis; this viewpoint originates from previous literature, and our case serves merely as an illustration of this clinical phenomenon. Future prospective studies are needed to validate the mechanisms and advantages of this sequential strategy.