Quantitative Analysis of Parotid Sparing and Reducing Xerostomia Using Volumetric Modulated Arc Therapy in Oral Cancer Patients

Document Type : Original Paper

Authors

1 Radiation Oncology Department, Fortis Hospital,Mohali,Punjab,India.

2 Chief Medical Physicist Department of Radiation Oncology Fortis Hospital Sector 62, Phase 8, SAS Nagar Moahli-160062 Punjab India

3 Department of Radiation Oncology, LHDM & Dr. Prem Hospital, Panipat, Haryana

4 Department of Radiation oncology Fortis Hospital Sector 62, Phase 8 SAS Nagar Mohali - 160062 Punjab, India

5 Department of Physics, School of Sciences, Arts, Media and Mangement, Karunya Institute of Technology and Sciences, Coimbatore-641 114 Tamilnadu India

6 Department of Radiation Oncology Medanta The Medicity Gurgoan Haryana

7 Department of Radiation Oncology Fortis Hospital Sector 62, Phase 8 SAS Nagar Mohali - 160062 Punjab, India

8 Department of Radiation Oncology Fortis Hospital, Sector 62, Phase 8, SAS Nagar, Mohali - 160062 Punjab, India

Abstract

Introduction: In head and neck cancer (HNC) radiotherapy, parotid, submandibular, and minor salivary glands are often incidentally irradiated. Hence, Xerostomia is the most significant disabling side-effect, so it should be reduced to increase the quality of life. Volumetric Modulated Arc Therapy (VMAT) is an advanced technique in radiotherapy. The study was to evaluate the parotid dose and PTV coverage in post operated Oral cancer patients using VMAT technique.

Materials and methods: The authors generated VMAT plans for 14 post operated oral cancer patients, where primary disease crossed midline or nodal stage ≥ 2. The doses to the moderate high-risk volume of the clinical target volume (CTV) and planning target volume (PTV) were 60Gy in 30 fractions. The low-risk volume received a dose to the CTV and PTV of 54Gy in 30 fractions. Plans were made for each patient, and the dose to D95 and D98 of target volumes was analyzed. The mean dose of the whole parotid and parotid minus PTV volumes were analyzed and compared with target doses (D98 & D95).

Results: Median dose to the ipsilateral parotid gland was 54.45Gy and to the ipsilateral parotid gland minus PTV was 45.60Gy while to the contralateral parotid gland median dose was 16.31Gy, (mean is ranging from 14.01 to 17.06Gy) and to the contralateral parotid gland minus PTV was 14.92 (mean is ranging from 12.42 to 15.18Gy) after achieving the 95% coverage of PTV.

Conclusion: Better sparing of contralateral parotid glands with the help of VMAT technique in post-operative HNC patients is possible, which can prevent xerostomia in most patients.

Keywords

Main Subjects



Articles in Press, Accepted Manuscript
Available Online from 28 May 2022
  • Receive Date: 11 March 2022
  • Revise Date: 25 May 2022
  • Accept Date: 28 May 2022
  • First Publish Date: 28 May 2022