1.IntroductionLung cancer, particularly non-small cell lung cancer (NSCLC), which accounts for over 80% of all lung cancers, poses a significant global health issue and is a major cause of cancer-related deaths [1,2]. Age is a primary risk factor for NSCLC, with more than half of all patients being aged 70 or above, and 10% being aged 80 or above [3]. Compared to younger patients, elderly cancer patients with advanced age have more comorbidities and poorer performance status, and they are underrepresented in clinical trials [1,4]. Consequently, clinicians face challenges in selecting optimal treatment regimens for this patient population. Limited treatment options may lead to poorer survival outcomes for elderly cancer patients, as they may opt for less aggressive therapies to avoid potential drug toxicity and minimize the risk of surgical complications and mortality.Immune checkpoint inhibitors (ICIs) targeting programmed cell death 1(PD-1) and programmed cell death protein ligand 1(PD-L1) have revolutionized thoracic oncology treatment [5]. Nivolumab, a fully humanized immunoglobulin G4 monoclonal antibody, enhances T cell anti-tumor response by blocking PD-1 receptor binding to PD-L1 and programmed cell death protein ligand 2(PD-L2) [6]. In 2015, the U.S. Food and Drug Administration (FDA) approved nivolumab for lung cancer treatment, with a recommended dose of 3 mg/kg or a fixed dose of 240 mg administered intravenously every two weeks [1].Here, we report the case of a 91-year-old patient diagnosed with locally advanced non-small cell lung cancer and an Eastern Cooperative Oncology Group (ECOG) performance status score of 2. The patient received a personalized regimen of 32 cycles of initial low-dose, extended-interval nivolumab monotherapy. No serious adverse events occurred throughout the treatment course, achieving a partial response (PR) with a progression-free survival (PFS) of 31 months while maintaining good quality of life.