This study aims to learn about the long-term safety and effectiveness of personalized stereotactic body radiotherapy (SBRT) in patients with early-stage peripheral non-small cell lung cancer (NSCLC). Individualized SBRT is a specialized radiation technique that delivers precise, high-dose treatment while minimizing damage to surrounding normal tissues.

The main question it aims to answer is:

Does individualized SBRT maintain local tumor control and patient survival at 3 years without significant side effects?

Patients with early-stage peripheral NSCLC who are medically inoperable or refuse surgery, and who are scheduled to receive individualized SBRT as their standard treatment, will provide the data to assess the safety and efficacy of this personalized radiation approach.

Inclusion Criteria

• Participant or legal guardian provides written informed consent.
• Age ≥18 years; no upper age limit; male or female.
• Pathologically confirmed non-small-cell lung cancer (NSCLC) staged T1-2N0M0 (IA-IIA, AJCC 8th ed.).
• Peripheral tumor location: ≥2 cm from the proximal bronchial tree or any mediastinal structure.
• Medically inoperable (e.g., FEV1 <40 % predicted, DLCO <40 % predicted, NYHA class III-IV heart failure) or refusal of surgery.
• ECOG performance status 0-2.
• Life expectancy ≥6 months per investigator judgment.
• Measurable disease by RECIST 1.1.
• Adequate organ function (blood counts, liver and renal indices) per institutional standards.
• Willing and able to comply with all study procedures, imaging schedules, and follow-up visits.
• Effective contraception for women of child-bearing potential and fertile men for 12 months after SBRT completion.

Exclusion Criteria

• Previous thoracic radiotherapy, chemotherapy, targeted therapy, or surgery for lung cancer.
• Evidence of regional or distant metastases.
• Concurrent or prior malignancy within 5 years (except adequately treated basal-cell carcinoma of skin or carcinoma in situ of cervix).
• Active interstitial pneumonitis, radiation pneumonitis, drug-induced pneumonitis, or clinically significant pulmonary fibrosis.
• Pregnancy, lactation, or planned pregnancy.
• Participation in another interventional clinical trial with an unmet primary endpoint.
• Known psychiatric disorder, substance abuse, or other condition that would impair compliance.
• Contraindication to contrast-enhanced CT or PET-CT imaging.
• Investigator-determined medical, social, or psychological contraindications that could compromise safety or data integrity.