Systemic treatment patterns and adherence to guidelines in Japanese patients with metastatic non-small cell lung cancer

Non-small-cell-lung cancer (NSCLC) medication use and guideline adherence remain unclear. We investigated treatment patterns and adherence among Japanese patients with NSCLC. We analyzed treatment patterns and guideline adherence by age and histology in ≥ 20-year-olds with stage IV NSCLC treated between 2016–2018 using diagnostic procedure combination data. Logistic regression analysis evaluated the impact of various factors on guideline adherence. We included 9,722 patients. In < 75-year-olds with nonsquamous NSCLC, first-to third-line treatments comprised 31.8% platinum combination therapy, 26.3% immune checkpoint inhibitors, and 62.5% cytotoxic chemotherapy. In ≥ 75-year-olds, first-line and second-line molecular targeted therapies represented 46.6% and 35.6%, whereas third-line cytotoxic chemotherapy represented 42.3%. In squamous NSCLC, first-line platinum combination therapy was predominant (69.7% and 47.7% for < 75-and ≥75-year-olds). The most common second-line and third-line therapies were immune checkpoint inhibitors (48.6% and 50.8% for < 75-and ≥75-year-olds) and cytotoxic chemotherapy (62.5% and 55.2% for < 75-and ≥75-year-olds), respectively. The highest guideline adherence (90%) was in < 75-year-olds with squamous NSCLC. Age, histology, activities of daily living, and cumulative hospitalizations over the past 18 months influenced treatment adherence. New NSCLC drug introduction increased regardless of age, suggesting prognosis improvement. More efficient drug application and broader guideline dissemination are required. This study examined how treatments for advanced non-small cell lung cancer (NSCLC) have evolved in Japan since the introduction of immune checkpoint inhibitors. These are a type of drug that helps to boost the immune system by blocking signals that normally prevent it from attacking cancer cells. Since their introduction, immune checkpoint inhibitors have become an important part of NSCLC treatment. Using the Japanese Diagnostic Procedure Combination database is a nationwide medical database in Japan that collects information on patients from hospitals treating acute conditions. This data includes details such as diagnoses, medical treatments, medications used, and hospitalization information. The researchers looked at patterns in treatment, from 2016 to present day. This time period is important because this is when immune checkpoint inhibitors began being used in treatment. Findings reveal significant changes in treatment approaches following the introduction of these new therapies. The study identifies areas where medical guidelines are well- followed, ensuring patients receive best possible treatment according to medical guidelines. However, it also highlights challenges, such as not following guidelines as much among younger patients with nonsquamous NSCLC, suggesting the need for targeted strategies to improve sharing and using medical guidelines. Understanding these treatment patterns is crucial for improving how well patients do after treatment and helping improve future healthcare rules. By providing insights into how doctors actually treat patients in everyday life and following medical guidelines in Japan, this study contributes valuable information that can guide doctors, nurses, and policymakers worldwide in optimizing NSCLC treatment strategies.