title: Changes in Tumor Volumes and Spatial Locations Relative to Normal Tissues During Cervical Cancer Radiotherapy Assessed by Cone Beam Computed Tomography.
abstract: To assess changes in the volumes and spatial locations of tumors and surrounding organs by cone beam computed tomography during treatment for cervical cancer.
  
  
  
  Sixteen patients with cervical cancer had intensity-modulated radiotherapy and off-line cone beam computed tomography during chemotherapy and/or radiation therapy. The gross tumor volume (GTV-T) and clinical target volumes (CTVs) were contoured on the planning computed tomography and weekly cone beam computed tomography image, and changes in volumes and spatial locations were evaluated using the volume difference method and Dice similarity coefficients.
  
  
  
  The GTV-T was 79.62 cm3at prior treatment (0f) and then 20.86 cm3at the end of external-beam chemoradiation. The clinical target volume changed slightly from 672.59 cm3to 608.26 cm3, and the uterine volume (CTV-T) changed slightly from 83.72 cm3to 80.23 cm3. There were significant differences in GTV-T and CTV-T among the different groups ( P < .001), but the clinical target volume was not significantly different in volume ( P > .05). The mean percent volume changes ranged from 23.05% to 70.85% for GTV-T, 4.71% to 6.78% for CTV-T, and 5.84% to 9.59% for clinical target volume, and the groups were significantly different ( P < .05). The Dice similarity coefficient of GTV-T decreased during the course of radiation therapy ( P < .001). In addition, there were significant differences in GTV-T among different groups ( P < .001), and changes in GTV-T correlated with the radiotherapy ( P < .001). There was a negative correlation between volume change rate (DV) and Dice similarity coefficient in the GTV-T and organs at risk ( r < 0; P < .05).
  
  
  
  The volume, volume change rate, and Dice similarity coefficient of GTV-T were all correlated with increase in radiation treatment. Significant variations in tumor regression and spatial location occurred during radiotherapy for cervical cancer. Adaptive radiotherapy approaches are needed to improve the treatment accuracy for cervical cancer.
authors.affiliation: 1 Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Fujian Medical University Cancer Hospital, Fuzhou, China.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Chen
authors.affiliation: 1 Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Fujian Medical University Cancer Hospital, Fuzhou, China.
authors.forename: Penggang
authors.initials: P
authors.lastname: Bai
authors.affiliation: 1 Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Fujian Medical University Cancer Hospital, Fuzhou, China.
authors.forename: Jianji
authors.initials: J
authors.lastname: Pan
authors.affiliation: 1 Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Fujian Medical University Cancer Hospital, Fuzhou, China.
authors.forename: Yuanji
authors.initials: Y
authors.lastname: Xu
authors.affiliation: 1 Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Fujian Medical University Cancer Hospital, Fuzhou, China.
authors.forename: Kaiqiang
authors.initials: K
authors.lastname: Chen
mesh_terms: D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D009038:Motion; D056888:Patient Positioning; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided; D050397:Radiotherapy, Intensity-Modulated; D047368:Tumor Burden; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*
keywords: Dice similarity coefficient; cervical cancer; cone beam computed tomography; image-guided radiation therapy; volume change rate