title: Analysis of Lung Tumor Motion in a Large Sample: Patterns and Factors Influencing Precise Delineation of Internal Target Volume.
abstract: To evaluate lung tumor motion during respiration and to describe factors affecting the range and variability of motion in patients treated with stereotactic ablative radiation therapy.
  
  
  
  Log file analysis from online respiratory tumor tracking was performed in 145 patients. Geometric tumor location in the lungs, tumor volume and origin (primary or metastatic), sex, and tumor motion amplitudes in the superior-inferior (SI), latero-lateral (LL), and anterior-posterior (AP) directions were recorded. Tumor motion variability during treatment was described using intrafraction/interfraction amplitude variability and tumor motion baseline changes. Tumor movement dependent on the tumor volume, position and origin, and sex were evaluated using statistical regression and correlation analysis.
  
  
  
  After analysis of >500 hours of data, the highest rates of motion amplitudes, intrafraction/interfraction variation, and tumor baseline changes were in the SI direction (6.0 ± 2.2 mm, 2.2 ± 1.8 mm, 1.1 ± 0.9 mm, and -0.1 ± 2.6 mm). The mean motion amplitudes in the lower/upper geometric halves of the lungs were significantly different (P<.001). Motion amplitudes >15 mm were observed only in the lower geometric quarter of the lungs. Higher tumor motion amplitudes generated higher intrafraction variations (R=.86, P<.001). Interfraction variations and baseline changes >3 mm indicated tumors contacting mediastinal structures or parietal pleura. On univariate analysis, neither sex nor tumor origin (primary vs metastatic) was an independent predictive factor of different movement patterns. Metastatic lesions in women, but not men, showed significantly higher mean amplitudes (P=.03) and variability (primary, 2.7 mm; metastatic, 4.9 mm; P=.002) than primary tumors.
  
  
  
  Online tracking showed significant irregularities in lung tumor movement during respiration. Motion amplitude was significantly lower in upper lobe tumors; higher interfraction amplitude variability indicated tumors in contact with mediastinal structures, although adhesion to parietal pleura did not necessarily reduce tumor motion amplitudes. The most variable lung tumors were metastatic lesions in women.
authors: Department of Oncology, University Hospital Ostrava, Ostrava, Czech Republic; VŠB-Technical University of Ostrava, Ostrava, Czech Republic.
authors: Lukas
authors: L
authors: Knybel
authors: Department of Oncology, University Hospital Ostrava, Ostrava, Czech Republic. Electronic address: Jakub.cvek@fno.cz.
authors: Jakub
authors: J
authors: Cvek
authors: Department of Oncology, University Hospital Ostrava, Ostrava, Czech Republic.
authors: Lukas
authors: L
authors: Molenda
authors: Department of Oncology, University Hospital Ostrava, Ostrava, Czech Republic.
authors: Natalie
authors: N
authors: Stieberova
authors: Department of Oncology, University Hospital Ostrava, Ostrava, Czech Republic.
authors: David
authors: D
authors: Feltl
mesh_terms: D000704:Analysis of Variance; D019583:Dose Fractionation, Radiation; D005260:Female; D056973:Four-Dimensional Computed Tomography; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy* / Q000556:secondary; D008297:Male; D009038:Motion; D009068:Movement; D016634:Radiosurgery; D012044:Regression Analysis; D012119:Respiration; D012737:Sex Factors; D013997:Time Factors; D047368:Tumor Burden