The First Reported Case of Treating the Ultra-Central Thorax With Cone Beam Computed Tomography-Guided Stereotactic...

Area of Science:

• Radiation Oncology
• Medical Physics
• Thoracic Oncology

Background:

• Stereotactic body radiotherapy (SBRT) for central and ultra-central thoracic tumors carries risks of severe adverse events.
• Adaptive SBRT techniques aim to improve precision and motion management for better outcomes.
• Ultra-central tumors pose unique challenges due to proximity to critical organs.

Observation:

• A novel approach, cone beam computed tomography (CBCT)-guided stereotactic adaptive radiotherapy (CT-STAR), was applied to an 80-year-old patient with ultra-central non-small cell lung cancer (NSCLC).
• Treatment involved 55 Gy in five fractions using a strict isotoxicity planning approach, prioritizing organ at risk (OAR) constraints.
• Daily CBCTs were used for real-time plan adaptation based on daily anatomy, with plan selection based on dose-volume histogram comparisons.

Findings:

• The adapted plan was superior and used for three of five treatment fractions.
• CT-STAR demonstrated improved target coverage in two fractions.
• The adaptive technique successfully resolved an organ at risk hard constraint violation in one fraction.

Implications:

• This case report supports the viability and dosimetric advantages of CT-STAR for treating challenging ultra-central NSCLC.
• CT-STAR may offer an improved toxicity profile and effective local control for these difficult-to-treat tumors.
• Further clinical data are required to validate the efficacy and safety of CT-STAR in a larger patient cohort.