PDF icon Download PDF
Open Access
CC BY-NC-ND 4.0 · South Asian J Cancer 2018; 07(01): 55-57
DOI: 10.4103/sajc.sajc_183_17
ORIGINAL ARTICLE: Head and Neck Cancer

Prospective study of sequential volumetric changes of parotid gland in early oropharyngeal carcinoma patients treated by intensity-modulated radiation therapy: An institutional experience

Pooja Nandwani Patel
Department of Radiotherapy, Gujarat Cancer and Research Institute, Ahmedabad, Gujarat
,
Sumit Goyal
Department of Radiotherapy, Gujarat Cancer and Research Institute, Ahmedabad, Gujarat
,
Anand Shah
Community Oncology, Gujarat Cancer and Research Institute, Ahmedabad, Gujarat, India
,
Mehul Gohel
Department of Radiotherapy, Gujarat Cancer and Research Institute, Ahmedabad, Gujarat
,
Unnikrishnan Suryanarayana
Department of Radiotherapy, Gujarat Cancer and Research Institute, Ahmedabad, Gujarat
› Author Affiliations
Financial support and sponsorship Nil.
› Further Information
Also available ateRef
 PDF Download Permissions and Reprints
Preview

Abstract

Aims and Objectives: During course of radiation therapy, anatomical variations occur risking overdose of parotid gland. We tried to quantify volume of parotid gland and mean dose to parotid gland after every 10 fractions (#). Materials and Methods: We conducted the prospective study from July 2016 to May 2017 in 25 patients of early-stage oropharyngeal carcinoma. Patients had Karnofsy Performance Score of 80–100, median age was 54 years, and 18 patients were males. Patients were planned with intensity-modulated radiation therapy planning with dose as 66 Gy/30# to planning target volume (PTV) including primary and 54 Gy/30# to PTV-nodal including elective neck irradiation. After each 10#, replanning was done, and variations in parotid volume were studied including Dmean(mean dose to parotids) and D50(the dose delivered to 50% of volume). Other tumor characteristic like PTV of primary was also assessed and minimum PTV volume covered by 95% isodose line was kept as 95%. Results: Average parotid volumes decreased by the mean value of 10% and 6% for the left and right parotids, respectively, and PTV of primary target decreased by mean of 13%. The difference in Dmeandoses to parotid glands was 32% and 42% and difference in D50dose was 30% and 35% on the left and right side, respectively. Conclusions: The parotid volumes differ considerably during adaptive planning done after every ten fractions. These differences in parotid volumes and doses received to parotid glands play a significant role in the risk of xerostomia observed during later follow-up.

Key words

Intensity-modulated radiation therapy - oropharyngeal carcinoma - parotid gland


Publication History

Article published online:
22 December 2020

© 2018. 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 Chambers MS, Rosenthal DI, Weber RS. Radiation-induced xerostomia. Head Neck 2007;29:58-63.
  • 2 Nutting CM, Morden JP, Harrington KJ, Urbano TG, Bhide SA, Clark C, et al. Parotid-sparing intensity modulated versus conventional radiotherapy in head and neck cancer (PARSPORT): A phase 3 multicentre randomised controlled trial. Lancet Oncol 2011;12:127-36.
  • 3 Pow EH, Kwong DL, McMillan AS, Wong MC, Sham JS, Leung LH, et al. Xerostomia and quality of life after intensity-modulated radiotherapy vs. Conventional radiotherapy for early-stage nasopharyngeal carcinoma: Initial report on a randomized controlled clinical trial. Int J Radiat Oncol Biol Phys 2006;66:981-91.
  • 4 Kam MK, Leung SF, Zee B, Chau RM, Suen JJ, Mo F, et al. Prospective randomized study of intensity-modulated radiotherapy on salivary gland function in early-stage nasopharyngeal carcinoma patients. J Clin Oncol 2007;25:4873-9.
  • 5 Lee C, Langen KM, Lu W, Haimerl J, Schnarr E, Ruchala KJ, et al. Assessment of parotid gland dose changes during head and neck cancer radiotherapy using daily megavoltage computed tomography and deformable image registration. Int J Radiat Oncol Biol Phys 2008;71:1563-71.
  • 6 O'Daniel JC, Garden AS, Schwartz DL, Wang H, Ang KK, Ahamad A, et al. Parotid gland dose in intensity-modulated radiotherapy for head and neck cancer: Is what you plan what you get? Int J Radiat Oncol Biol Phys 2007;69:1290-6.
  • 7 Nishimura Y, Nakamatsu K, Shibata T, Kanamori S, Koike R, Okumura M, et al. Importance of the initial volume of parotid glands in xerostomia for patients with head and neck cancers treated with IMRT. Jpn J Clin Oncol 2005;35:375-9.
  • 8 You SH, Kim SY, Lee CG, Keum KC, Kim JH, Lee IJ, et al. Is there a clinical benefit to adaptive planning during tomotherapy in patients with head and neck cancer at risk for xerostomia? Am J Clin Oncol 2012;35:261-6.
  • 9 Duma MN, Kampfer S, Schuster T, Winkler C, Geinitz H. Adaptive radiotherapy for soft tissue changes during helical tomotherapy for head and neck cancer. Strahlenther Onkol 2012;188:243-7.
  • 10 Fiorino C, Rizzo G, Scalco E, Broggi S, Belli ML, Dell'Oca I, et al. Density variation of parotid glands during IMRT for head-neck cancer: Correlation with treatment and anatomical parameters. Radiother Oncol 2012;104:224-9.
  • 11 Schwartz DL, Garden AS, Shah SJ, Chronowski G, Sejpal S, Rosenthal DI, et al. Adaptive radiotherapy for head and neck cancer – Dosimetric results from a prospective clinical trial. Radiother Oncol 2013;106:80-4.
  • 12 Nishi T, Nishimura Y, Shibata T, Tamura M, Nishigaito N, Okumura M, et al. Volume and dosimetric changes and initial clinical experience of a two-step adaptive intensity modulated radiation therapy (IMRT) scheme for head and neck cancer. Radiother Oncol 2013;106:85-9.
  • 13 Hansen EK, Bucci MK, Quivey JM, Weinberg V, Xia P. Repeat CT imaging and replanning during the course of IMRT for head-and-neck cancer. Int J Radiat Oncol Biol Phys 2006;64:355-62.
  • 14 Wu Q, Chi Y, Chen PY, Krauss DJ, Yan D, Martinez A, et al. Adaptive replanning strategies accounting for shrinkage in head and neck IMRT. Int J Radiat Oncol Biol Phys 2009;75:924-32.