Journal: International journal of cancer
This population-based study used Japan’s National Cancer Registry (2016–2020) to examine how the route of detection influences stage at diagnosis, initial treatment, and survival in lung cancer.
Patient groups (n = 563,244):
- Screening-detected: 16.9% (95,081)
- Incidentally detected (e.g., work-up for other conditions): 45.2% (254,569)
- Other detection pathways (e.g., symptomatic presentation): 35.7% (200,850)
Key clinical characteristics:
- Older adults (≥65 years) across groups:
- Screening: 69.5%
- Incidental: 88.6%
- Other: 83.4%
- Proportion with localized disease at diagnosis:
- Screening: 50.5%
- Incidental: 49.6%
- Other: 14.0%
Initial treatment patterns:
- Surgery as the most common first treatment:
- Screening group: 62.5%
- Incidental group: 46.2%
- Chemotherapy as the predominant first treatment:
- Other group: 48.6%
Net survival (NS):
- Overall 3‑year NS:
- Screening: 75.2% (95% CI 74.9–75.6)
- Incidental: 56.3% (56.0–56.6)
- Other: 29.4% (29.2–29.7)
- 3‑year NS among patients with localized disease:
- Screening: 96.3% (95.9–96.7)
- Incidental: 83.9% (83.6–84.3)
- Other: 76.9% (76.1–77.6)
Interpretation: Detection via organized screening is associated with earlier stage at diagnosis, greater use of surgery, and substantially better 3‑year net survival, supporting the role of screening and a favorable diagnostic environment in improving outcomes for lung cancer in Japan.