Bar‐Ad, Voichita

Abstract Purpose: To quantitatively predict the impact of cardiopulmonary dose on overall survival (OS) after radiotherapy for locally advanced non–small cell lung cancer. Experimental Design: We used the NRG Oncology/RTOG 0617 dataset. The model building procedure was preregistered on a public website. Patients were split between a training and a set-aside validation subset (N = 306/131). The 191 candidate variables covered disease, patient, treatment, and dose-volume characteristics from multiple cardiopulmonary substructures (atria, lung, pericardium, and ventricles), including the minimum dose to the hottest x% volume (Dx%[Gy]), mean dose of the hottest x% (MOHx%[Gy]), and minimum, mean (Mean[Gy]), and maximum dose. The model building was based on Cox regression and given 191 candidate variables; a Bonferroni-corrected P value threshold of 0.0003 was used to identify predictors. To reduce overreliance on the most highly correlated variables, stepwise multivariable analysis (MVA) was repeated on 1000 bootstrapped replicates. Multivariate sets selected in ≥10% of replicates were fit to the training subset and then averaged to generate a final model. In the validation subset, discrimination was assessed using Harrell c-index, and calibration was tested using risk group stratification. Results: Four MVA models were identified on bootstrap. The averaged model included atria D45%[Gy], lung Mean[Gy], pericardium MOH55%[Gy], and ventricles MOH5%[Gy]. This model had excellent performance predicting OS in the validation subset (c = 0.89). Conclusions: The risk of death due to cardiopulmonary irradiation was accurately modeled, as demonstrated by predictions on the validation subset, and provides guidance on the delivery of safe thoracic radiotherapy.

Objectives/HypothesisTo evaluate the utility of positron emission tomography (PET)/computed tomography (CT) for staging the neck in the preoperative setting by comparing it to both CT/magnetic resonance imaging (MRI) and pathologic staging.Study DesignRetrospective review.MethodsSeventy‐one patients with initial diagnosis of head and neck squamous cell carcinoma having preoperative MR or CT imaging and PET/CT with subsequent bilateral neck dissection as part of primary treatment (142 neck dissections). Comparison of cervical nodal metastases based on three separate staging systems: preoperative CT and/or MRI scan, preoperative PET/CT, and pathology.ResultsBoth CT/MRI scans and PET/CT scans statistically predicted pathologic outcomes (P = 0.0001, P = 0.0001, respectively) using Chi square analysis. There was a statistically significant improvement in the prediction of true pathologic disease using PET/CT compared to CT and/or MRI alone (P = 0.005). In a subgroup analysis including only the contralateral neck, this significance persisted (P = 0.013). McNemar's test revealed that subsequent detection of bilateral neck disease by PET/CT scan was significantly superior to MRI or CT alone (P = 0.023).ConclusionIn pathologically positive necks, PET/CT was statistically more reliable at identifying positive disease than CT or MRI alone. Furthermore, such a result is achieved without a statistically significant difference in false positivity between PET/CT and CT or MRI. This suggests that PET/CT positivity, despite negative clinical exam and CT/MRI findings, may be more likely to signify pathologic disease and require appropriate treatment.Level of Evidence4. Laryngoscope, 124:159–164, 2014