Optimization of Treatment Parameters for Post Mastectomy Electron Therapy of Defected Chest-Wall

Document Type : Original Article (s)

Authors

1 Resident, Department of Radiotherapy, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

2 Associate Professor, Department of Medical Physics and Engineering, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

3 Assistant Professor, Department of Radiotherapy, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

Abstract

Background: Electrons have an advantage of steep dose fall-off after R80. The unique curved geometry of the chest-wall and the special isodose shapes of electrons make complexities to chest-wall electron therapy. Bolus material has been applied to electron fields for shaping the coverage of planned volume and compensating for surface irregularities. Electron bolus conformal therapy methods are not yet vastly available; therefore, this study tries to extrapolate suggestions for conventional usage of bolus and different electron beam energies.Methods: Computer plans for 10 post-mastectomy patients with at least 1cm elevated or depressed surgical defects were designed. Bolus thicknesses of 5, 10, and 15 mm and electron energies of 9, 12, 15, and 18 MeV were applied to the clinical target volume. Average doses to the surface, clinical target volume (CTV1), ipsilateral lung and heart were calculated by the planning system and then analyzed.Findings: High energies of electrons and thicker bolus reduced the risk of CTV1 underdose. Bolus increases surface dose whereas decreases mean dose to CTV. Nine MeV electrons and bolus was unsuitable for this type of treatment. In most treatments the dose increase to lung was statistically significant (P < 0.01) with higher energies of electrons and lower thicknesses of bolus. This was not observed for the heart.Conclusion: Careful design of bolus thickness is important when planning with lower energy electrons. This study suggests that planning with thicker bolus material and higher energy selection has advantage of dose conformity with conventional methods of electron therapy in a defected surface.

Keywords

References

  1. Huang EY, Wang CJ, Chen HC, Sun LM, Fang FM, Yeh SA, et al. Multivariate analysis of pulmonary fibrosis after electron beam irradiation for postmastectomy chest wall and regional lymphatics: evidence for non-dosimetric factors. Radiother Oncol 2000; 57(1): 91-6.
  2. White J, Tai A, Arthur D, Buchholz T, MacDonald S, Marks L, et al. Breast cancer atlas for radiation therapy planning: Consensus definition. Philadelphia, PA: Radiation Therapy Oncology Group; 2011.
  3. The National Comprehensive Cancer Network (NCCN). NCCN clinical practice guidelines in oncology (NCCN guidelines). Fort Washington, PA: NCCN; 2013.
  4. Perkins GH, McNeese MD, Antolak JA, Buchholz TA, Strom EA, Hogstrom KR. A custom three-dimensional electron bolus technique for optimization of postmastectomy irradiation. Int J Radiat Oncol Biol Phys 2001; 51(4): 1142-51.
  5. Recht A, Edge SB, Solin LJ, Robinson DS, Estabrook A, Fine RE, et al. Postmastectomy radiotherapy: clinical practice guidelines of the American Society of Clinical Oncology. J Clin Oncol 2001; 19(5): 1539-69.
  6. Spierer MM, Hong LX, Wagman RT, Katz MS, Spierer RL, McCormick B. Postmastectomy CT-based electron beam radiotherapy: dosimetry, efficacy, and toxicity in 118 patients. Int J Radiat Oncol Biol Phys 2004; 60(4): 1182-9.
  7. Overgaard M, Hansen PS, Overgaard J, Rose C, Andersson M, Bach F, et al. Postoperative radiotherapy in high-risk premenopausal women with breast cancer who receive adjuvant chemotherapy. Danish Breast Cancer Cooperative Group 82b Trial. N Engl J Med 1997; 337(14): 949-55.
  8. Overgaard M, Jensen MB, Overgaard J, Hansen PS, Rose C, Andersson M, et al. Postoperative radiotherapy in high-risk postmenopausal breast-cancer patients given adjuvant tamoxifen: Danish Breast Cancer Cooperative Group DBCG 82c randomised trial. Lancet 1999; 353(9165): 1641-8.
  9. Ragaz J, Olivotto IA, Spinelli JJ, Phillips N, Jackson SM, Wilson KS, et al. Locoregional radiation therapy in patients with high-risk breast cancer receiving adjuvant chemotherapy: 20-year results of the British Columbia randomized trial. J Natl Cancer Inst 2005; 97(2): 116-26.
  10. Rutqvist LE, Rose C, Cavallin-Stahl E. A systematic overview of radiation therapy effects in breast cancer. Acta Oncol 2003; 42(5-6): 532-45.
  11. Whelan TJ, Julian J, Wright J, Jadad AR, Levine ML. Does locoregional radiation therapy improve survival in breast cancer? A meta-analysis. J Clin Oncol 2000; 18(6): 1220-9.
  12. Wennberg B, Gagliardi G, Sundbom L, Svane G, Lind P. Early response of lung in breast cancer irradiation: radiologic density changes measured by CT and symptomatic radiation pneumonitis. Int J Radiat Oncol Biol Phys 2002; 52(5): 1196-206.
  13. Halperin EC, Brady LW, Perez CA, Wazer DE. Perez and Bradys principles and practice of radiation oncology. 6th ed. Philadelphia, PA: Lippincott Williams and Wilkins; 2013.
  14. Khan FM, Gibbons JP. Khan's the physics of radiation therapy. 5th ed. Philadelphia, PA: Lippincott Williams and Wilkins; 2014.
  15. Kudchadker RJ, Hogstrom KR, Garden AS, McNeese MD, Boyd RA, Antolak JA. Electron conformal radiotherapy using bolus and intensity modulation. Int J Radiat Oncol Biol Phys 2002; 53(4): 1023-37.
  16. Low DA, Starkschall G, Bujnowski SW, Wang LL, Hogstrom KR. Electron bolus design for radiotherapy treatment planning: bolus design algorithms. Med Phys 1992; 19(1): 115-24.
  17. Pierce LJ, Butler JB, Martel MK, Normolle DP, Koelling T, Marsh RB, et al. Postmastectomy radiotherapy of the chest wall: dosimetric comparison of common techniques. Int J Radiat Oncol Biol Phys 2002; 52(5): 1220-30.
  18. Nedaie HA, Mosleh-Shirazi MA, Allahverdi M. Monte Carlo N Particle code - Dose distribution of clinical electron beams in inhomogeneous phantoms. J Med Phys 2013; 38(1): 15-21.
Journal of Isfahan Medical School
Volume 34, Issue 383 - Serial Number 383
March and April 2016
Pages 547-554

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History

  • Receive Date: 29 October 2015
  • Revise Date:
  • Accept Date: 06 April 2022

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