Prospective imaging comparison of anatomic delineation with rapid kV cone beam CT on a novel ring gantry radiotherapy device.

INTRODUCTION: A kV imager coupled to a novel, ring-gantry radiotherapy system offers improved on-board kV-cone-beam computed tomography (CBCT) acquisition time (17-40 seconds) and image quality, which may improve CT radiotherapy image-guidance and enable online adaptive radiotherapy. We evaluated whether inter-observer contour variability over various anatomic structures was non-inferior using a novel ring gantry kV-CBCT (RG-CBCT) imager as compared to diagnostic-quality simulation CT (simCT). MATERIALS/METHODS: Seven patients undergoing radiotherapy were imaged with the RG-CBCT system at breath hold (BH) and/or free breathing (FB) for various disease sites on a prospective imaging study. Anatomy was independently contoured by seven radiation oncologists on: 1. SimCT 2. Standard C-arm kV-CBCT (CA-CBCT), and 3. Novel RG-CBCT at FB and BH. Inter-observer contour variability was evaluated by computing simultaneous truth and performance level estimation (STAPLE) consensus contours, then computing average symmetric surface distance (ASSD) and Dice similarity coefficient (DSC) between individual raters and consensus contours for comparison across image types. RESULTS: Across 7 patients, 18 organs-at-risk (OARs) were evaluated on 27 image sets. Both BH and FB RG-CBCT were non-inferior to simCT for inter-observer delineation variability across all OARs and patients by ASSD analysis (p < 0.001), whereas CA-CBCT was not (p = 0.923). RG-CBCT (FB and BH) also remained non-inferior for abdomen and breast subsites compared to simCT on ASSD analysis (p < 0.025). On DSC comparison, neither RG-CBCT nor CA-CBCT were non-inferior to simCT for all sites (p > 0.025). CONCLUSIONS: Inter-observer ability to delineate OARs using novel RG-CBCT images was non-inferior to simCT by the ASSD criterion but not DSC criterion.

Early Mortality in Patients Undergoing Adjuvant Chemotherapy for Non-Small Cell Lung Cancer.

BACKGROUND: Although adjuvant chemotherapy improves survival in patients with completely resected NSCLC, it is also associated with potentially disabling or lethal adverse events. Because there is limited information on the early mortality among patients undergoing adjuvant chemotherapy, we used the National Cancer Database to calculate the percentage of deaths within the first 6 months of starting chemotherapy. METHODS: The National Cancer Database was queried for patients age 18 or older in whom stage IB to IIIA NSCLC had been diagnosed between 2004 and 2012 and who had received multiagent adjuvant chemotherapy starting within 120 days from the surgical resection with negative surgical margins. Age groups were divided as follows: younger than 50, 51 to 60, 61 to 70, 71 to 80, and older than 80 years. RESULTS: A total of 19,691 patients met the eligibility criteria, 19,398 of whom had a known 6-month mortality status. The median age was 65 years (range 19-89). The 1-, 2-, 3-, 4-, 5-, and 6-month cumulative mortality rates from initiation of chemotherapy were 0.7%, 1.3%, 1.9%, 2.6%, 3.2%, and 4.1% respectively. The 6-month mortality rates for each age group (≤ 50 years, 51-60, 61-70, 71-80, and >80) were 2.6%, 3.1%, 4.1%, 5.3%, and 7.6%, respectively (p < 0.001). Independent factors associated with increased 6-month mortality included age 71 to 80 versus younger than 50 (OR = 1.72, 95% confidence interval [CI]: 1.16-2.55, p = 0.007), age older than 80 versus younger than 50 (OR = 2.43, 95% CI: 1.40-4.20, p = 0.002), male sex (OR = 1.42; 95% CI: 1.21-1.67, p < 0.001), Charlson-Deyo comorbidity score of 2 versus 0 (OR = 1.52, 95% CI 1.22-1.89, p < 0.001), pneumonectomy (OR = 1.38, 95% CI: 1.11-1.73, p = 0.004), length of postopertive stay longer than 6 days after surgery (OR = 1.21, 95% CI: 1.03-1.41, p = 0.02), and readmission within 30 days from surgery (OR = 1.48, 95% CI: 1.15-1.90, p = 0.02). CONCLUSIONS: Early mortality with the use of adjuvant chemotherapy after complete resection of NSCLC is a clinical concern. The risk is higher in patients older than 70 years, with higher comorbidity scores and a prolonged length of stay postoperatively.