Efficacy and Safety of S-1 Monotherapy in Previously Treated Elderly Patients (aged ≥75 years) with Non-small Cell Lung Cancer: A Retrospective Analysis

Background: S-1 monotherapy is effective and feasible for previously treated patients with advanced non-small cell lung cancer (NSCLC). However, it is not clear whether its effectiveness and tolerability in elderly patients are equivalent to those in younger patients. Hence, this study aimed to evaluate the efficacy and feasibility of S-1 monotherapy in elderly patients with NSCLC who had previously received other treatments.

Methods: We included 96 elderly patients (aged ≥75 years) with advanced NSCLC treated with S-1 alone as a subsequent-line treatment at 12 medical facilities between January 2005 and March 2018 in this study. The baseline characteristics of the patients, response to S-1 monotherapy, and adverse events (AEs) were investigated, retrospectively.

Results: A total of 68 male and 28 female patients (median age, 78 [range: 75-86] years) were analyzed. In elderly patients who were treated with S-1 monotherapy as a subsequent-line treatment, the objective response rate, disease control rate, median progression-free survival (PFS), and overall survival (OS) were 8.3%, 43.8%, 3.4 months, and 9.6 months, respectively. Observed AEs included anorexia, anemia, nausea, fatigue, reduced platelet count, and skin hyperpigmentation. Treatment-related death was observed in one patient because of pneumonitis. In patients who experienced no progressive disease, subsequent-line S-1 alone was associated with longer PFS and OS.

Conclusions: S-1 monotherapy is effective and feasible as a subsequent-line treatment in elderly patients who were previously treated for NSCLC, and it produces results. S-1 monotherapy could be one of the treatment choices for elderly patients with previously treated NSCLC.