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Quantification of volumetric and geometric changes occurring during fractionated radiotherapy for head-and-neck cancer using an integrated CT/linear accelerator system.

Publication ,  Journal Article
Barker, JL; Garden, AS; Ang, KK; O'Daniel, JC; Wang, H; Court, LE; Morrison, WH; Rosenthal, DI; Chao, KSC; Tucker, SL; Mohan, R; Dong, L
Published in: Int J Radiat Oncol Biol Phys
July 15, 2004

PURPOSE: Many patients receiving fractionated radiotherapy (RT) for head-and-neck cancer have marked anatomic changes during their course of treatment, including shrinking of the primary tumor or nodal masses, resolving postoperative changes/edema, and changes in overall body habitus/weight loss. We conducted a pilot study to quantify the magnitude of these anatomic changes with systematic CT imaging. METHODS AND MATERIALS: Fourteen assessable patients were enrolled in this pilot study. Eligible patients had to have a pathologic diagnosis of head-and-neck cancer, be treated with definitive external beam RT, and had have gross primary and/or cervical nodal disease measuring at least 4 cm in maximal diameter. All patients were treated using a new commercial integrated CT-linear accelerator system (EXaCT) that allows CT imaging at the daily RT sessions while the patient remains immobilized in the treatment position. CT scans were acquired three times weekly during the entire course of RT, and both gross tumor volumes (GTVs: primary tumor and involved lymph nodes) and normal tissues (parotid glands, spinal canal, mandible, and external contour) were manually contoured on every axial slice. Volumetric and positional changes relative to a central bony reference (the center of mass of the C2 vertebral body) were determined for each structure. RESULTS: Gross tumor volumes decreased throughout the course of fractionated RT, at a median rate of 0.2 cm(3) per treatment day (range, 0.01-1.95 cm(3)/d). In terms of the percentage of the initial volume, the GTVs decreased at a median rate of 1.8%/treatment day (range, 0.2-3.1%/d). On the last day of treatment, this corresponded to a median total relative loss of 69.5% of the initial GTV (range, 9.9-91.9%). In addition, the center of the mass of shrinking tumors changed position with time, indicating that GTV loss was frequently asymmetric. At treatment completion, the median center of the mass displacement (after corrections for daily setup variation) was 3.3 mm (range, 0-17.3 mm). Parotid glands also decreased in volume (median, 0.19 cm(3)/d range, 0.04-0.84 cm(3)/d), and generally shifted medially (median, 3.1 mm; range, 0-9.9 mm) with time. This medial displacement of the parotid glands correlated highly with the weight loss that occurred during treatment. CONCLUSION: Measurable anatomic changes occurred throughout fractionated external beam RT for head-and-neck cancers. These changes in the external contour, shape, and location of the target and critical structures appeared to be significant during the second half of treatment (after 3-4 weeks of treatment) and could have potential dosimetric impact when highly conformal treatment techniques are used. These data may, therefore, be useful in the development of an adaptive RT scheme (periodic adjustment of the conformal treatment plan) that takes into account such treatment-related anatomic changes. In theory, such a strategy would maximize the therapeutic ratio of RT.

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Published In

Int J Radiat Oncol Biol Phys

DOI

ISSN

0360-3016

Publication Date

July 15, 2004

Volume

59

Issue

4

Start / End Page

960 / 970

Location

United States

Related Subject Headings

  • Weight Loss
  • Tomography, X-Ray Computed
  • Pilot Projects
  • Particle Accelerators
  • Parotid Gland
  • Oncology & Carcinogenesis
  • Middle Aged
  • Male
  • Lymph Nodes
  • Humans
 

Citation

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Barker, J. L., Garden, A. S., Ang, K. K., O’Daniel, J. C., Wang, H., Court, L. E., … Dong, L. (2004). Quantification of volumetric and geometric changes occurring during fractionated radiotherapy for head-and-neck cancer using an integrated CT/linear accelerator system. Int J Radiat Oncol Biol Phys, 59(4), 960–970. https://doi.org/10.1016/j.ijrobp.2003.12.024
Barker, Jerry L., Adam S. Garden, K Kian Ang, Jennifer C. O’Daniel, He Wang, Laurence E. Court, William H. Morrison, et al. “Quantification of volumetric and geometric changes occurring during fractionated radiotherapy for head-and-neck cancer using an integrated CT/linear accelerator system.Int J Radiat Oncol Biol Phys 59, no. 4 (July 15, 2004): 960–70. https://doi.org/10.1016/j.ijrobp.2003.12.024.
Barker JL, Garden AS, Ang KK, O’Daniel JC, Wang H, Court LE, et al. Quantification of volumetric and geometric changes occurring during fractionated radiotherapy for head-and-neck cancer using an integrated CT/linear accelerator system. Int J Radiat Oncol Biol Phys. 2004 Jul 15;59(4):960–70.
Barker, Jerry L., et al. “Quantification of volumetric and geometric changes occurring during fractionated radiotherapy for head-and-neck cancer using an integrated CT/linear accelerator system.Int J Radiat Oncol Biol Phys, vol. 59, no. 4, July 2004, pp. 960–70. Pubmed, doi:10.1016/j.ijrobp.2003.12.024.
Barker JL, Garden AS, Ang KK, O’Daniel JC, Wang H, Court LE, Morrison WH, Rosenthal DI, Chao KSC, Tucker SL, Mohan R, Dong L. Quantification of volumetric and geometric changes occurring during fractionated radiotherapy for head-and-neck cancer using an integrated CT/linear accelerator system. Int J Radiat Oncol Biol Phys. 2004 Jul 15;59(4):960–970.
Journal cover image

Published In

Int J Radiat Oncol Biol Phys

DOI

ISSN

0360-3016

Publication Date

July 15, 2004

Volume

59

Issue

4

Start / End Page

960 / 970

Location

United States

Related Subject Headings

  • Weight Loss
  • Tomography, X-Ray Computed
  • Pilot Projects
  • Particle Accelerators
  • Parotid Gland
  • Oncology & Carcinogenesis
  • Middle Aged
  • Male
  • Lymph Nodes
  • Humans