One Fraction Simulation-Free Treatment With CT-Guided Stereotactic Adaptive Radiotherapy for Patients With Oligometastatic and Primary Lung Tumors

Stereotactic body radiotherapy (SBRT) has become a standard of care for medically inoperable or high-risk operable early-stage non-small cell lung cancer (NSCLC) patients. It is also increasingly used to treat lung metastases in patients with oligometastatic disease. While SBRT is a powerful tool for the treatment of lung tumors, access to specialized treatment can be limited for patients who live far away from a treatment center. Geographic accessibility can be limiting even for patients receiving one fraction lung SBRT, as the typical consult, CT simulation, and one-fraction treatment workflow is typically at least two to three weeks from start to finish, with a minimum of three in-person appointments. In this study, a high-quality cone beam CT (CBCT) on-board imaging platform (HyperSight; Varian Medical Systems, Palo Alto, CA) will be coupled with advanced motion management and treatment techniques as well as Ethos (Varian Medical Systems, Palo Alto, CA) daily online adaptation to simulation-free workflow for one fraction SBRT. This has the potential to reduce the time it takes a patient to be cured of their lung tumor from two to three weeks to two to three hours. In this novel workflow, patients will undergo telephone/online consent followed by a diagnostic scan-based pre-plan for one fraction SBRT. On the morning of treatment, a brief follow-up appointment will be followed by treatment on the HyperSight/Ethos platform. Patients will be treated using a simulation-free workflow. A HyperSight Thorax Slow protocol CBCT will be acquired for study purposes, and then the patient will be treated with online adaptive CBCT-guided radiotherapy on the Ethos/HyperSight platform. Treatment delivery will take place following contouring and treatment planning. Patients will undergo standard of care simulation imaging in parallel for comparison. The purpose of this study is to evaluate the feasibility of a ONE fraction Simulation-free Treatment with CT-guided stereotactic adaptive radiotherapy for Oligometastatic and Primary lung tumors (ONE STOP) workflow for patients with small, peripheral primary or oligometastatic lung tumors.