Functionally weighted airway sparing (FWAS): a functional avoidance method for preserving post-treatment ventilation...

Area of Science:

• Radiation Oncology
• Pulmonary Medicine
• Medical Imaging

Background:

• Lung cancer screening guidelines have evolved, increasing focus on preserving post-radiotherapy lung function.
• Current methods prioritize sparing functional lung regions but may overlook damage to peripheral airways.
• Damage to these airways, crucial for gas exchange, can impair overall lung function.

Purpose of the Study:

• To introduce and evaluate the functionally weighted airway sparing (FWAS) method for preserving lung function after SAbR.
• To address the limitation of current functional avoidance strategies by incorporating airway preservation.
• To reduce post-SAbR loss of respiratory function by protecting critical bronchial pathways.

Main Methods:

• Developed FWAS to map bronchial pathways, assign function-based weights to airways, and create treatment plans prioritizing airway preservation.
• Utilized CT scans and ventilation maps from SAbR patients to estimate airway contribution to lung function.
• Incorporated airway radiosensitivity models to set dose constraints and used an optimization engine for 3D conformal SAbR plan creation.

Main Results:

• FWAS plans demonstrated superior preservation of lung ventilation compared to prescribed and inverse-optimized clinical plans.
• Ventilation improvements ranged from 3% to 23% over prescribed plans and 3% to 35% over inverse-optimized plans.
• All plans met clinical requirements for planning target volume coverage and organs at risk dose constraints.

Conclusions:

• The FWAS method effectively spares functional pathways, leading to better preservation of post-SAbR lung function.
• Protecting airways that supply high-functioning lung subregions is crucial for mitigating respiratory decline.
• FWAS represents a promising approach to enhance functional outcomes in lung cancer SAbR.