Radiobiological Model-Based Comparison of Three-Dimensional Conformal and Intensity-Modulated Radiation Therapy Plans for Nasopharyngeal Carcinoma

Document Type: Original Paper

Authors

1 Tabriz University of Medical Sciences

2 Medical Physics department, Tabriz University of Medical Sciences

3 Radiation Oncology Department, Imam Reza Hospital, Tabriz, Iran

4 Radiation oncology department, Tabriz university of medical sciences

Abstract

Introduction: Radiobiological modeling of radiotherapy plans are used for treatment plan comparisons. The current study aimed to compare the three-dimensional conformal radiation therapy (3DCRT) and intensity-modulated radiation therapy (IMRT) plans for nasopharyngeal cancer using radiobiological modeling.
Materials and Methods: This study was conducted on 10 patients with nasopharyngeal carcinoma, who were planned for 3DCRT and IMRT treatments by using the TiGRT treatment planning system. The planning target volume (PTV) doses of 70 and 72 Gy were administered for the 3DCRT and IMRT plans, respectively. The BIOLPLAN software and the Niemierko’s equivalent uniform dose (EUD) model were utilized for the estimation of tumor control probability (TCP) and normal tissue complication probability (NTCP). The NTCPs of the spinal cord, brain stem, parotid glands, middle ears, temporomandibular joints (TMJ), mandible, and thyroid were calculated by using two radiobiological models.
Results: According to the results, the mean TCPs for 3DCRT and IMRT plans were 89.92%±8.92 and 94.9%±3.86, respectively, showing no statistically significant difference (P=0.08). The NTCPs of the parotid glands, thyroid gland, spinal cord, TMJ, and mandible were considerably lower in the IMRT plans, compared to those in the 3DCRT plans. On the other hand, the calculated NTCPs for the middle ears and brain stem increased for the IMRT plans, which were not statistically significant. On average, the NTCPs of the critical organs were lower based on the EUD model than the Lyman-Kutcher-Burman model.
Conclusion: From the radiobiological point of view, the IMRT plans were significantly advantageous over the 3DCRT plans with some small variations in each patient. On average, the two radiobiological models generated different NTCPs depending on the studied organs. Consequently, more studies are needed for the optimization of radiobiological models for the prediction of the treatment outcomes in radiation therapy.

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References

 

  1. Ferreira BC, do Carmo LM, Mateus J, Capela M, Mavroidis P: Radiobiological evaluation of forward and inverse IMRT using different fractionations for head and neck tumours. Radiat Oncol 2010;5:57. doi: 10.1186/1748-717X-5-57.:57-5.
  2. Narayanasamy G, Pyakuryal AP, Pandit S, Vincent J, Lee C, Mavroidis P, Papanikolaou N, Kudrimoti M, Sio TT: Radiobiological evaluation of intensity modulated radiation therapy treatments of patients with head and neck cancer: A dual-institutional study. J Med Phys 2015;40:165-169.
  3. Taheri-Kadkhoda Z, Pettersson N, Bjork-Eriksson T, Johansson KA: Superiority of intensity-modulated radiotherapy over three-dimensional conformal radiotherapy combined with brachytherapy in nasopharyngeal carcinoma: a planning study. Br J Radiol 2008;81:397-405.
  4. Peters LJ, Withers HR: Applying radiobiological principles to combined modality treatment of head and neck cancer--the time factor. Int J Radiat Oncol Biol Phys 1997;39:831-836.
  5. Wu PM, Chua DT, Sham JS, Leung L, Kwong DL, Lo M, Yung A, Choy DT: Tumor control probability of nasopharyngeal carcinoma: a comparison of different mathematical models. Int J Radiat Oncol Biol Phys 1997;37:913-920.
  6. Roberts SA, Hendry JH: A realistic closed-form radiobiological model of clinical tumor-control data incorporating intertumor heterogeneity. Int J Radiat Oncol Biol Phys 1998;41:689-699.
  7. Zhong H, Chetty I: A note on modeling of tumor regression for estimation of radiobiological parameters. Med Phys 2014;41:081702.
  8. Moiseenko V, Battista J, Van DJ: Normal tissue complication probabilities: dependence on choice of biological model and dose-volume histogram reduction scheme. Int J Radiat Oncol Biol Phys 2000;46:983-993.
  9. Oinam AS, Singh L, Shukla A, Ghoshal S, Kapoor R, Sharma SC: Dose volume histogram analysis and comparison of different radiobiological models using in-house developed software. J Med Phys 2011;36:220-229.
  10. Surega A, Punitha J, Sajitha S, Ramesh B, Pichandi A, Sasikala P: A statistical quantification of radiobiological metrics in Intensity Modulated Radiation Therapy evaluation. Gulf J Oncolog 2015;1:15-23.
  11. Mesbahi A, Dadgar H: Dose calculations accuracy of TiGRT treatment planning system for small IMRT beamlets in heterogeneous lung phantom. 2015;13:345-354.
  12. Mesbahi A, Zergoug I: Dose calculations for lung inhomogeneity in high-energy photon beams and small beamlets: A comparison between XiO and TiGRT treatment planning systems and MCNPX Monte Carlo code. 2015;12:167-177.
  13. Marks LB, Ten Haken RK, Martel MK: Guest editor's introduction to QUANTEC: a users guide. Int J Radiat Oncol Biol Phys 2010;76:S1-S2.
  14. Sanchez-Nieto B, Nahum AE: BIOPLAN: software for the biological evaluation of. Radiotherapy treatment plans. Med Dosim 2000;25:71-76.
  15. Gay HA, Niemierko A: A free program for calculating EUD-based NTCP and TCP in external beam radiotherapy. Phys Med 2007;23:115-125.
  16. Bakhshandeh M, Hashemi B, Mahdavi SR, Nikoofar A, Vasheghani M, Kazemnejad A: Normal tissue complication probability modeling of radiation-induced hypothyroidism after head-and-neck radiation therapy. Int J Radiat Oncol Biol Phys 2013;85:514-521.
  17. Kam MK, Chau RM, Suen J, Choi PH, Teo PM: Intensity-modulated radiotherapy in nasopharyngeal carcinoma: dosimetric advantage over conventional plans and feasibility of dose escalation. Int J Radiat Oncol Biol Phys 2003;56:145-157.