Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-23T11:42:36.241Z Has data issue: false hasContentIssue false

Retrospective dosimetric evaluation of VMAT plans for prostate cancer treatment

Published online by Cambridge University Press:  29 November 2018

Johnson Darko*
Affiliation:
Department of Medical Physics, Grand River Regional Cancer Centre, Kitchener, Ontario, Canada Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
Ernest Osei
Affiliation:
Department of Medical Physics, Grand River Regional Cancer Centre, Kitchener, Ontario, Canada Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada Department of Systems Design, University of Waterloo, Waterloo, Ontario, Canada Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
Andre Fleck
Affiliation:
Department of Medical Physics, Grand River Regional Cancer Centre, Kitchener, Ontario, Canada Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
Ramana Rachakonda
Affiliation:
Department of Radiation Oncology, Grand River Regional Cancer Centre, Kitchener, Ontario, Canada
*
Author for correspondence: Johnson Darko, Department of Medical Physics, Grand River Regional Cancer Centre, Kitchener, ON, Canada N2G 1G3. Tel: 519 749 4300/5793. E-mail: [email protected]

Abstract

Background

Radiation therapy (RT) remains a common and effective treatment modality for patients with locally advanced prostate cancer. Technological advancements over the past decade have resulted in the introduction of intensity-modulated radiation therapy (IMRT) planning and delivery techniques that maximise the dose of radiation delivered to the prostate while sparing organs at risk (OAR). A more recent and evolving IMRT technique, called volumetric-modulated arc therapy (VMAT), involves a continuous irradiation at a constant or variable dose rate when the gantry rotates around the prostate using one or more arcs.

Materials and methods

This paper reports on a dosimetric evaluation of our implementation of VMAT technique for prostate cancer treatment. A retrospective analysis of VMAT plans was performed for 300 prostate cancer patients treated during the period of January 2013 to December 2014. Two prescription cohorts of patients treated to a dose of 78 Gy in 39 fractions as the primary radiation therapy treatment (XRT) and 66 Gy in 33 fractions as a post-op or salvage XRT were considered.

Results

The mean and maximal doses, dose inhomogeneities and conformity indexes for the planning target volumes were evaluated for each prescription cohort of patients. Similarly, the doses to OAR such as rectum, bladder and femoral heads were also assessed for various dose levels.

Conclusion

This study shows that highly conformal radiation dose distribution for the treatment of prostate cancer is achievable with the VMAT technique. It provides evidence to support the adoption of such conformal technology in many disease sites such as the prostate. We believe that our experience reported here could help form the foundation for individual institutions to evaluate and develop the most suitable planning criteria tailored to their own needs and priority. This endeavour hopefully will provide further improvement in the planning process and, therefore, help achieve an effective and efficient delivery of radiotherapy for prostate cancer.

Type
Original Article
Copyright
© Cambridge University Press 2018 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

Cite this article: Darko J, Osei E, Fleck A, Rachakonda R (2019) Retrospective dosimetric evaluation of VMAT plans for prostate cancer treatment. Journal of Radiotherapy in Practice18: 155–164. doi: 10.1017/S1460396918000596

References

1. Jemal, A, Siegel, R, Xu, J, Ward, E. Cancer statistics, 2010. CA Cancer J Clin 2010; 60 (5): 277300.Google Scholar
2. Amin, N, Konski, A A. Intensity-modulated radiation therapy for prostate cancer is cost effective and improves therapeutic ratio. Expert Rev Pharmacoeconomics Outcomes Res 2012; 12 (4): 447450.Google Scholar
3. Shaffer, R, Morris, W, Moiseenko, V et al. Volumetric modulated arc therapy and conventional intensity-modulated radiotherapy for simultaneous maximal intraprostatic boost: a planning comparison study. Clin Oncol 2009; 21 (5): 401407.Google Scholar
4. Intensity Modulated Radiation Therapy Collaborative Working Group. Intensity-modulated radiotherapy: current status and issues of interest. Int J Radiat Oncol Biol Phys 2001; 51 (4): 880914.Google Scholar
5. Plowman, P. Recent London improvements in curative radiation therapy for relevant early prostate cancer. Ann N Y Acad Sci 2008; 1138 (1): 257266.Google Scholar
6. Otto, K. Volumetric modulated arc therapy: IMRT in a single gantry arc. Med Phys 2008; 35 (1): 310317.Google Scholar
7. Palma, D, Vollans, E, James, K et al. Volumetric modulated arc therapy for delivery of prostate radiotherapy: comparison with intensity-modulated radiotherapy and three-dimensional conformal radiotherapy. Int J Radiat Oncol Biol Phys 2008; 72 (4): 9961001.Google Scholar
8. Davidson, M T, Blake, S J, Batchelar, D L, Cheung, P, Mah, K. Assessing the role of volumetric modulated arc therapy (VMAT) relative to IMRT and helical tomotherapy in the management of localized, locally advanced, and post-operative prostate cancer. Int J Radiat Oncol Biol Phys 2011; 80 (5): 15501558.Google Scholar
9. Hall, W A, Fox, T H, Jiang, X et al. Treatment efficiency of volumetric modulated arc therapy in comparison with intensity-modulated radiotherapy in the treatment of prostate cancer. J Am Coll Radiol 2013; 10 (2): 128134.Google Scholar
10. Fontenot, J D, King, M, Johnson, S, Wood, C, Price, M, Lo, K. Single-arc volumetric-modulated arc therapy can provide dose distributions equivalent to fixed-beam intensity-modulated radiation therapy for prostatic irradiation with seminal vesicle and/or lymph node involvement. Br J Radiol 2012; 85 (1011): 231236.Google Scholar
11. Tsai, C, Wu, J, Chao, H, Tsai, Y, Cheng, J C. Treatment and dosimetric advantages between VMAT, IMRT, and helical tomotherapy in prostate cancer. Med Dosim 2011; 36 (3): 264271.Google Scholar
12. Wolff, D, Stieler, F, Welzel, G et al. Volumetric modulated arc therapy (VMAT) vs. serial tomotherapy, step-and-shoot IMRT and 3D-conformal RT for treatment of prostate cancer. Radiother Oncol 2009; 93 (2): 226233.Google Scholar
13. Leibel, S A, Fuks, Z, Zelefsky, M J et al. Technological advances in external-beam radiation therapy for the treatment of localized prostate cancer. Semin Oncol 2003; 30 (5): 596615.Google Scholar
14. de Crevoisier, R, Tucker, S L, Dong, L et al. Increased risk of biochemical and local failure in patients with distended rectum on the planning CT for prostate cancer radiotherapy. Int J Radiat Oncol Biol Phys 2005; 62 (4): 965973.Google Scholar
15. Zietman, A L, DeSilvio, M L, Slater, J D et al. Comparison of conventional-dose vs high-dose conformal radiation therapy in clinically localized adenocarcinoma of the prostate: a randomized controlled trial. J Am Med Assoc 2005; 294 (10): 12331239.Google Scholar
16. Guckenberger, M, Richter, A, Krieger, T, Wilbert, J, Baier, K, Flentje, M. Is a single arc sufficient in volumetric-modulated arc therapy (VMAT) for complex-shaped target volumes? Radiother Oncol 2009; 93 (2): 259265.Google Scholar
17. Kopp, R W, Duff, M, Catalfamo, F, Shah, D, Rajecki, M, Ahmad, K. VMAT vs. 7-field-IMRT: assessing the dosimetric parameters of prostate cancer treatment with a 292-patient sample. Med Dosim 2011; 36 (4): 365372.Google Scholar
18. Dearnaley, D, Sydes, M, Graham, J et al. On behalf of the RT01 collaborators Escalated-dose versus standard-dose conformal radiotherapy in prostate cancer: first results from the MRC RT01 randomised controlled trial. Lancet Oncol 2007; 8 (6): 475487.Google Scholar
19. Yoo, S, Wu, Q J, Lee, W R, Yin, F F. Radiotherapy treatment plans with RapidArc for prostate cancer involving seminal vesicles and lymph nodes. Int J Radiat Oncol Biol Phys 2010; 76 (3): 935942.Google Scholar
20. Shaw, E, Kline, R, Gillin, M et al. Radiation Therapy Oncology Group: radiosurgery quality assurance guidelines. Int J Radiat Oncol Biol Phys 1993; 27 (5): 12311239.Google Scholar
21. Knoos, T, Kristensen, I, Nilsson, P. Volumetric and dosimetric evaluation of radiation treatment plans: radiation conformity index. Int J Radiat Oncol Biol Phys 1998; 42 (5): 11691176.Google Scholar
22. Khan, M I, Jiang, R, Kiciak, A, Ur Rehman, J, Afzal, M, Chow, J C. Dosimetric and radiobiological characterizations of prostate intensity-modulated radiotherapy and volumetric-modulated arc therapy: a single-institution review of ninety cases. J Med Phys 2016; 41 (3): 162168.Google Scholar
23. Michalski, J M, Gay, H, Jackson, A, Tucker, S L, Deasy, J O. Radiation dose-volume effects in radiation-induced rectal injury. Int J Radiat Oncol Biol Phys 2010; 76 (3 Suppl): S1239.Google Scholar