This study aims to explore the safety and efficacy of eliminating the PTV (planning target volume) margins based on online adaptive stereotactic radiotherapy for patients with centrally located early-stage non-small cell lung cancer (NSCLC).

Inclusion Criteria:

• Histologically confirmed untreated early-stage non-small cell lung cancer (T1-2N0M0), or recurrent disease (rT1-2N0M0) that is inoperable or where the patient is unwilling to undergo surgery.
• Centrally located lung cancer.
• Age 18 years or older, regardless of gender.
• ECOG performance status score of 0-2.
• Serum hemoglobin ≥ 80 g/L, platelets ≥ 100,000/μL, absolute neutrophil count ≥ 1,500/μL.
• Serum creatinine ≤ 1.25 times the upper normal limit (UNL) or creatinine clearance ≥ 60 ml/min.
• Serum bilirubin ≤ 1.5 times UNL, AST (SGOT) and ALT (SGPT) ≤ 2.5 times UNL, alkaline phosphatase ≤ 5 times UNL.
• FEV1 ≥ 0.5 L.
• Normal CB6 range.
• The patient and their family agree and sign the informed consent form.

Exclusion Criteria:

• Any other disease or condition that contraindicates radiotherapy (e.g., active infections, within 6 months post-myocardial infarction, symptomatic heart disease including unstable angina, congestive heart failure, or uncontrolled arrhythmias).
• Pregnant or breastfeeding women, women who have not undergone pregnancy testing, and pregnant individuals.
• Individuals with substance abuse issues, chronic alcoholism, or AIDS.
• Individuals with uncontrollable seizures or loss of self-control due to psychiatric disorders.
• Individuals with a history of severe allergies or specific sensitivities.