Abstract: Currently, lung cancer remains one of the deadliest cancers, with a very high mortality rate, accounting for approximately 18% of all cancer-related deaths. Non-small cell lung cancer (NSCLC) accounts for 80% of all lung cancer deaths. In particular, elderly patients generally have poor tolerance to chemotherapy or cannot tolerate chemotherapy. This case analysis focuses on an elderly patient with non-small cell lung cancer stage IV. The patient was an 86-year-old female with poor nutritional status and low body weight (27 kg) and could not tolerate platinum-based dual-drug first-line chemotherapy. This patient had tumour cells in alveolar lavage fluid without conditions examined for pd-l1 expression. However, the efficacy of previous first-line immunotherapy was positive, and the patient and his family members agreed to apply it, so there was no contraindication to apply anlotinib + pembrolizumab. Results were reviewed after two cycles, and CR was used to evaluate the efficacy. After four cycles, the efficacy was evaluated as complete remission (CR), the patient developed immune-related side effects, immunotherapy was suspended, and maintenance therapy with anlotinib was used. The most recent review was in 2023-6-9, and PET/CT indicated that the patient had sustained CR. In general, this case provides support for the successful possibility of a treatment strategy for elderly patients with poor physical fitness who cannot tolerate platinum-based doublet chemotherapy and who have driver gene-negative squamous cell lung cancer (PS> 0-1).

Keywords: pembrolizumab, immune checkpoint inhibitors, non-small cell lung cancer, case report, anlotinib