BACKGROUND AND PURPOSE: The present study investigates the extent and appearance of radiologic injury in the lung after radiotherapy for non-small cell lung cancer (NSCLC) patients and correlates radiologic response with clinical and dosimetric factors.
METHODS AND MATERIALS: Eligible follow-up CT scans acquired up to six months after radiotherapy were evaluated for radiologic injuries in 220 NSCLC patients. Radiologic injuries were divided into three categories: (1) interstitial changes, (2) ground-glass opacity, or (3) consolidation. The relationship between the fraction of injured lung of each category and clinical or dosimetric factors was investigated.
RESULTS: Radiological injuries of category 1-3 were found in 67%, 52%, and 51% of the patients, and the mean (and maximum) fraction of injured lung was 4.4% (85.9%), 2.4% (46.0%), and 2.1% (22.9%), respectively. Traditional lung dose metrics and time to follow-up predicted lung injury of all categories. Older age increased the risk of interstitial changes and current smoking reduced the risk of consolidation in the lung.
CONCLUSION: Radiologic injuries were frequently found in follow-up CT scans after radiotherapy for NSCLC patients. The risk of a radiologic response increased with increasing time and lung dose metrics, and depended on patient age and smoking status.