Extent and computed tomography appearance of early radiation induced lung injury for non-small cell lung cancer.

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.