2478 - Quality-of-Life Metrics Correlate with Dual-Energy and 4D CT Derived Perfusion and Ventilation in Lung Cancer Patients 6 Months Post Radiation Therapy

Purpose/Objective(s): To investigate quality-of-life (QoL) and lung function changes following definitive chemoradiation dose using dual-energy (DE) and 4D CT scans in patients with locally advanced NSCLC at 6 months post-treatment compared to pre-treatment.

Materials/Methods: Consecutive patients receiving definitive radiation (60-70 Gy at 200 cGy/fx, IMRT [n=12] or Proton RT [n=10]) with concurrent chemotherapy were enrolled on an IRB approved prospective trial. QoL was evaluated using MD Anderson Symptom Inventory (MDASI) and UCSD shortness of breath questionnaire (SOBQ), completed at baseline, 3 months, and 6 months post-RT. Patients were dichotomized based on the Minimal Clinically Important Difference (MCID) in MDASI of 8 points and MCID in UCSD SOBQ of 5 points. All patients underwent contrast-enhanced DE and 4D CT scans prior to radiation and 6 months post-RT. Pre-RT and post-RT perfusion and ventilation maps were generated using DE CT and 4D CT datasets. Perfusion Blood Volume (PBV) was derived from DE CT by quantifying the contrast agent per voxel, while ventilation maps were generated by registering the inhale-phase to the exhale-phase image and computing the Jacobian determinant of the resulting transformation. Perfusion and ventilation data were processed using commercially available software. Statistical analysis was performed using GraphPad PRISM v10.4.1 (GraphPad Software, San Diego, CA).

Results: We evaluated QoL and CT-derived lung function changes after 6 months of lung-RT (n=22, Male/Female=11/11). There were 6 (27%) patients that experienced a change in MDASI > MCID and 10 (45%) patients that had a ?UCSD SOBQ > MCID between baseline and 6 months follow-up. There was a significant difference (p<0.05) between baseline and follow-up perfusion in regions receiving >20Gy, >30Gy, and >40Gy radiation dose, as well as between baseline and follow-up ventilation in regions receiving >30Gy, >40Gy, and >50Gy radiation dose. MDASI severity at baseline significantly correlated with longitudinal changes in perfusion in regions receiving >5Gy (?=0.49, p=0.02). MDASI severity and interference at 3 months showed significant correlations with changes in ventilation in regions receiving <5Gy (?=0.54, p=0.01 and ?=0.53, p=0.01, respectively). Changes in MDASI interference significantly correlated with baseline ventilation in regions receiving <5Gy (?=0.45, p=0.04). Ventilation in regions receiving >5Gy independently predicted ?MDASI > MCID (AUC=0.80), while ventilation in regions receiving <5Gy (AUC=0.72) and >40Gy (AUC=0.72) predicted ?UCSD SOBQ > MCID.

Conclusion: We identified baseline CT ventilation measurements that independently predicted and correlated with longitudinal worsening in QoL, measured using MDASI and UCSD SOBQ. In addition, changes in DE CT derived perfusion correlated with MDASI scores, suggesting that routine CT derived measurements can be used to detect clinically significant changes in lung cancer patients 6 months post-RT.