Download PDF
CC BY-NC-ND 4.0 · South Asian J Cancer 2014; 03(01): 022-027
DOI: 10.4103/2278-330X.126510
THE CUTTING EDGE OF RADIOTHERAPEUTICS : Original Article

Prescribed dose versus calculated dose of spinal cord in standard head and neck irradiation assessed by 3-D plan

Dipanjan Majumder
Department of Radiotherapy, Medical College Kolkata, Kolkata, West Bengal
,
Niladri Bihari Patra
Department of Radiotherapy, Medical College Kolkata, Kolkata, West Bengal
,
Debashis Chatterjee
Department of Radiotherapy, Medical College Kolkata, Kolkata, West Bengal
,
Swapan Kumar Mallick
Department of Radiotherapy, Medical College Kolkata, Kolkata, West Bengal
,
Niladri Bihari Patra
Department of Radiotherapy, Medical College Kolkata, Kolkata, West Bengal
,
Apurba Kumar Kabasi
Department of Radiotherapy, Medical College Kolkata, Kolkata, West Bengal
,
Anjali Majumder
Department of Radiotherapy, Medical College Kolkata, Kolkata, West Bengal
› Author Affiliations Source of Support: Nill.
› Further Information
  PDF Download Permissions and Reprints

Abstract

Background and Purpose: Spinal cord toxicity can be dreaded complication while treating head and neck cancer by conventional radiotherapy. Cord sparing approach is applied by two phase planning in conventional head neck radiotherapy. In spite of cord sparing approach spinal cord still receives considerable scatter dose. Our study aims to do the volumetric analysis of spinal cord dosimetry and to correlate with the clinical findings. Materials and Methods: Treatment planning was done in two phases. First phase treatment fi elds include gross disease- both tumor and involved nodes. in the second phase, treatment field shrinkage was done to cover the gross disease sparing the spinal cord. These fields are termed as off-cord fields. 42 patients with histological proven squamous cell carcinoma of the head and neck region were analysed with two groups. In Group A, 46 Gy was given in 23 fractions, and then tumor-boost with off-cord fi eld received 24 Gy in 12 fractions. In Group B 50 Gy was prescribed in 25 fractions initially, then off-cord fi eld given 20 Gy in 10 fractions to analyze theoutcome. Planning Computed tomography (CT) scan was done Philips Brilliance 16 slice CT scan machine, and contouring and dose calculation were done at ASHA treatment planning software. Results: Maximum dose and dose at 1 cm3, 2 cm3, and 5 cm3 were calculated. Maximum dose to cord was 52.6 Gy (range 48.1-49.7 Gy) in Group A and 54.3 Gy (range 51.48-52.33 Gy) in Group B initially. Off-cord fi elds received mean dose 8.07 Gy (85.85% of maximum) in Group A and 5.47 Gy (86.84% of maximum) in Group B. At the end of 6 months from the last date of radiotherapy, grade 1 spinal cord toxicity found in two patients in Group A and one patient in Group B respectively (P = 0.55). Both groups received additional dose, which are higher than the prescribed dose, but no patients show significant spinal cord toxicity after 6 month of follow-up. Conclusion: Spinal cord received scatter dose which much higher than the predicted dose in conventional radiotherapy of head neck cancer. Short term follow up failed to establish clinical correlation with volumetric dose of spinal cord. Two phase cord sparing head neck radiation planning if practiced should be used with caution.

Head neck cancer - off-cord field - spinal cord - volumetric analysis


Publication History

Article published online:
31 December 2020

© 2014. MedIntel Services Pvt Ltd. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/.)

Thieme Medical and Scientific Publishers Pvt. Ltd.
A-12, 2nd Floor, Sector 2, Noida-201301 UP, India

 

  • References

  • 1 Wong CS, Van Dyk J, Milosevic M, Laperriere NJ. Radiation myelopathy following single courses of radiotherapy and retreatment. Int J Radiat Oncol Biol Phys 1994;30:575-81.
  • 2 Abbatucci JS, Delozier T, Quint R, Roussel A, Brune D. Radiation myelopathy of the cervical spinal cord: Time, dose and volume factors. Int J Radiat Oncol Biol Phys 1978;4:239-48.
  • 3 Ang KK, Kaanders JH, Peters LJ. Practical aspects of external beam therapy. In: Ang KK, Kaanders JH, Peters LJ, editors. Radiotherapy for Head and Neck Cancers: Indications and Techniques. Ch. 3. Philadelphia, PA: Lea and Febiger; 1994. p. 15-9.
  • 4 Schultheiss TE. Spinal cord radiation tolerance. Int J Radiat Oncol Biol Phys 1994;30:735-6.
  • 5 Schultheiss TE. Spinal cord radiation "tolerance": Doctrine versus data. Int J Radiat Oncol Biol Phys 1990;19:219-21.
  • 6 Parsons JT. The effect of radiation on normal tissues of the head and neck. In: Million RR, Cassisi NJ, editors. Management of Head and Neck Cancer: A Multidisciplinary Approach. Philadelphia, PA: J.B Lippincott; 1994. p. 245-89.
  • 7 Wara WM, Phillips TL, Sheline GE, Schwade JG. Radiation tolerance of the spinal cord. Cancer 1975;35:1558-62.
  • 8 Marcus RB Jr, Million RR. The incidence of myelitis after irradiation of the cervical spinal cord. Int J Radiat Oncol Biol Phys 1990;19:3-8.
  • 9 McCunniff AJ, Liang MJ. Radiation tolerance of the cervical spinal cord. Int J Radiat Oncol Biol Phys 1989;16:675-8.
  • 10 Emami B, Lyman J, Brown A, Coia L, Goitein M, Munzenrider JE, et al. Tolerance of normal tissue to therapeutic irradiation. Int J Radiat Oncol Biol Phys 1991;21:109-22.
  • 11 Majumder D, Choudhury K, Das P, Kundu S, Mitra D. Different fractionation fractionation schedules of radiotherapy in locally advanced head and neck malignancy: A prospective randomized study to compare the results of treatment and toxicities of different protocols. South Asian J Cancer 2013; 2:31-5.
  • 12 Bedwinek JM, Perez CA. Carcinoma of the nasopharynx. In: Perez CA, Brady LW, editors. Principles and Practice of Radiation Oncology. Philadelphia, PA: J.B. Lippincott; 1987. p. 479-98.
  • 13 Kessler ML, Ten Haken RK, Fraass BA, McShan DL. Expanding the use and effectiveness of dose-volume histograms for 3-D treatment planning. I: Integration of 3-D dose-display. Int J Radiat Oncol Biol Phys 1994;29:1125-31.
  • 14 McShan DL, Fraass BA, Lichter AS. Full integration of the beam′s eye view concept into computerized treatment planning. Int J Radiat Oncol Biol Phys 1990;18:1485-94.
  • 15 McShan DL, Fraass BA. Use of an octree-like geometry for 3-D dose calculations. Med Phys 1993;20:1219-27.
  • 16 McShan DL, Fraass BA, Ten Haken RK. Dosimetric verification of a 3-D electron pencil beam dose calculation algorithm. Med Phys 1994;21:13-23.
  • 17 Fraass BA, McShan DL. 3-D treatment planning: I. Overview of a clinical planning system. In: Bruinvis I.A, D, editor. The Use of Computers in Radiation Therapy. Amsterdam: Elsevier; 1987. p. 273-6.
  • 18 Fraass BA, McShan DL, Ten Haken RK, Hutchins KM. 3-D treatment planning: V. A fast 3-D photon calculational model. In: Bruinvis IA, et al., editors. The Use of Computers in Radiation Therapy. Amsterdam: Elsevier; 1987. p. 521-5.
  • 19 Cox JD, Stetz J, Pajak TF. Toxicity criteria of the radiation therapy oncology group (RTOG) and the European organization for research and treatment of cancer (EORTC) Int J Radiat Oncol Biol Phys 1995;31:1341-6.
  • 20 Cohen L, Creditor M. An iso-effect table for radiation tolerance of the human spinal cord. Int J Radiat Oncol Biol Phys 1981;7:961-6.
  • 21 Wang CC. Technical considerations of radiation therapy of head/neck tumors. In: Radiation Therapy for Head and Neck Neoplasms: Indications, Techniques and Results, pp 50-52. Editor Wang CC. Year book medical, Chicago, IL, 1990.
  • 22 Reinhold HS, Kaalen JG, Unger-Gils K. Radiation myelopathy of the thoracic spinal cord. Int J Radiat Oncol Biol Phys 1976;1:651-7.
  • 23 Siegal T, Pfeffer MR. Radiation-induced changes in the profile of spinal cord serotonin, prostaglandin synthesis, and vascular permeability. Int J Radiat Oncol Biol Phys 1995;31:57-64.
  • 24 Kirkpatrick JP, Van der Kogel AJ, Schultheiss TE. The lessons of QUANTEC: Recommendations for reporting and gathering data on dose-volume dependencies of treatment outcome. Int J Radiat Oncol Biol Phys 2010;76:42-9.