Published in:
01-12-2012 | Research Article
Functional and biologic metrics for predicting radiation pneumonitis in locally advanced non-small cell lung cancer patients treated with chemoradiotherapy
Published in: Clinical and Translational Oncology | Issue 12/2012
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Objective
To study the predictive value of functional and biologic metrics for predicting radiation pneumonitis (RP) in locally advanced non-small cell lung cancer (LANSCLC) patients treated with chemoradiotherapy.
Methods
Between March 2006 and April 2010, 57 LANSCLC patients were enrolled in a prospective study. Fusion of SPECT and computed tomography scans provides perfusion-weighted functional dose–volume histogram (DVH) and associated functional dosimetric parameters. Blood for serum biomarkers—interleukin-6 (IL-6), transforming growth factor-beta1, and superoxide dismutase (SOD)—was drawn pre-RT and then 40 Gy/4 weeks during the treatment. The incidence of RP was related to the functional and biologic metrics. The predictability of predictors was calculated and compared based on the area under receiver-operating characteristic (ROC) curve (AUC).
Results
Relative volumes of functional lung receiving more than a threshold dose of 5–50 Gy at increments of 5 Gy and elevated levels of serum SOD after delivery of 40 Gy/4 weeks were associated with RP (p < 0.05). The best predictive efficacy of SOD was observed for a cutoff value of 56 U/ml, with a sensitivity of 0.80 (95 % CI 0.28–0.99) and a specificity of 0.67 (95 % CI 0.43–0.65) (p = 0.040). Functional DVH provided better predictive outcome (AUC 0.76–0.98) than standard DVH (AUC 0.62–0.86) for patients with poor baseline lung function.
Conclusion
Functional metrics were identified to be better predictors for RP in patients with poor baseline lung function. SOD seemed to be a potential predictor for RP; however, it will need to be further verified using a larger sample size.