SBRT for Ultra-Central NonSmall Cell Lung Cancer

Prior treatment

• Patients with previous radiation therapy to the thorax that would result in overlap with the planned treatment field.
• Patients receiving concurrent chemotherapy, immunotherapy, or targeted therapy during SBRT.
• Patients on Vascular Endothelial Growth Factor (VEGF) inhibitors.

Other illness

• Patients with active connective tissue disease (e.g., lupus, scleroderma, polymyositis, rheumatoid arthritis).
• Patients with interstitial lung disease of any etiology.
• Patients with evidence of endobronchial disease.
• Patients with psychiatric illness or social situation that would limit compliance with study requirements.

Other

• Patients with evidence of nodal involvement (N1-N3) or distant metastases (M1).
• Patients with tumor-associated bronchial compression, defined as visible deformation or narrowing of the trachea, mainstem bronchus, or bronchus intermedius on diagnostic CT, simulation CT, or bronchoscopy.
• Patients with tumor invasion of any major airways, esophagus, or major blood vessels.
• Patients who fail to place fiducial markers for Synchrony tracking.
• Patients who require alternate fractionation scheduling.
• Patients who are pregnant or are breastfeeding.
• Patients who are unable to lie flat for the duration of treatment (approximately 45-60 minutes per fraction).
• Patients who are unable to or unwilling to give informed consent.

• Patients aged 18 or older.
• Patients with an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.
• Patients with confirmed tumor location using advanced imaging to ensure accurate classification of ultra-central NSCLC.
• Ability to undergo bronchoscopy and Endobronchial ultrasound (EBUS) with adequate fiducial placement
• Histologically or cytologically confirmed clinical stage T1-T2 N0 M0 NSCLC (AJCC 9th edition), with maximum tumor diameter ≤5 cm.
• Absence of overt radiological or bronchoscopy assessed gross endobronchial invasion, invasion of the trachea, esophagus, major blood vessels, or other mediastinal structures.
• 4D-CT (computed tomography) scans will be required to evaluate tumor motion and verification at time of simulation:
  • ○ Screening for ultra-central tumor deformation between inhalation and exhalation extremities will be performed via 4D-CT to avoid inappropriate margins for significant tumor motion or deformation.
• Ultra-central tumors must include:
  • o Gross Tumor Volume (GTV) or Planning Target Volume (PTV) located within 1 cm (centimeter) of the Proximal Bronchial Tree (PBT) and/or at least one of the following: (1) GTV or protocol PTV within 1 cm of the PBT; or (2) GTV within 5 mm of or abutting/overlapping the esophagus, heart/pericardium, aorta, pulmonary artery, or pulmonary vein.
• Patients are eligible to receive SBRT:
  • Patients deemed suitable for SBRT based on multidisciplinary evaluation;
  • Medically inoperable, decline surgery or high surgical risk as determined by a thoracic surgeon or multidisciplinary tumor board;
  • No prior overlapping thoracic radiation exceeding dose constraints for critical structures;
  • Adequate pulmonary function to tolerate procedure;
  • A minimum of two gold fiducials will be placed in or adjacent to the tumor via bronchoscopy and will be tracked/evaluated by the treating radiation oncologist and/or physicist/dosimetrist to determine quality of fiducial placement for trial inclusion.
• Patients are eligible to receive radiation therapy:
  • Candidate for CyberKnife radiosurgery using Synchrony motion management;
  • 4D-CT is required to evaluate tumor motion. Patients with \>1.5 cm excursion in any dimension will require a 5 mm PTV margin and remain eligible only if all mandatory Organs-at-risk (OAR) dosimetric and planning constraints can be met; otherwise, they are ineligible for protocol treatment.
  • OAR constraints will be prioritized over target coverage. Patients who cannot meet mandatory airway, esophagus, great vessel, heart, spinal cord, and lung constraints are not eligible for protocol treatment.
• Female patients of childbearing potential must have a negative pregnancy test prior to treatment and agree to contraception during and for a defined period after treatment.
• Patients who can comply with follow-up visits and treatment plans.
• Patients who can provide written informed consent prior to study procedures.