**JoLT-Ca Study: Comparing Two Treatments for Lung Cancer** This study is trying to find out if a type of radiation treatment, called **Stereotactic Ablative Radiotherapy (SAbR)**, helps people with early-stage lung cancer live longer compared to **Sublobar Resection (SR)**, a type of surgery. Lung cancer types are often named by how cells look under a microscope, and this study focuses on **Non-Small Cell Lung Cancer (NSCLC)**, the most common type. **Key Points:** - **Duration**: Patients will be observed for at least two years after treatment. - **Participation**: Patients will be randomly assigned to either SAbR or SR but can choose to participate or not. - **Eligibility**: Must be over 18, have a confirmed specific type of lung cancer, and be considered high risk for surgery. Before joining, patients will go through a process to see if they fit the study's requirements, like having specific lung function tests. Only those who agree to join, after understanding all the details, will be part of the study. This research aims to improve lung cancer treatment options and help patients make informed decisions about their care.