Noncancerous Imaging Markers on Chest CT Performed Before SBRT Improve Survival Prediction

Noncancerous imaging markers on chest CT performed before stereotactic body radiation therapy (SBRT) improve survival prediction, compared with clinical features alone, according to a new study.

The retrospective study by researchers at the Massachusetts General Hospital (Boston, MA, USA) included 282 patients (168 female, 114 male; median age, 75 years) with stage I lung cancer treated with SBRT between January 2009 and June 2017. To quantify CAC score and PA-to-aorta ratio, as well as emphysema and body composition, pretreatment chest CT was used. Associations of clinical and imaging features with overall were quantified using a multivariable Cox proportional hazards (PH) model.

Image: Noncancerous chest CT features for predicting survival in stage I lung cancer (Photo courtesy of Pexels)

For stage I lung cancer patients treated with SBRT, CAC score, PA-to-aorta ratio, and skeletal muscle index showed significant independent associations with overall survival. (p<.05). The model including clinical and imaging features demonstrated better discriminatory ability for 5-year overall survival than the model including clinical features alone (AUC 0.75 vs. 0.61, p<.01).

“In patients undergoing SBRT for stage I lung cancer,” explained corresponding author and 2019 ARRS Scholar Florian J. Fintelmann, “higher coronary artery calcium (CAC) score, higher pulmonary artery (PA)-to-aorta ratio, and lower thoracic skeletal muscle index independently predicted worse overall survival.”

“The PA-to-aorta ratio, which is readily quantifiable with electronic calipers during routine image review, was the most important predictor of overall survival,” the authors concluded.

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Massachusetts General Hospital