Thomas J Galloway1, Robert J Amdur2, Chihray Liu1, Anamaria R Yeung1, William M Mendenhall1. 1. Department of Radiation Oncology, College of Medicine, University of Florida, Gainesville, Florida. 2. Department of Radiation Oncology, College of Medicine, University of Florida, Gainesville, Florida. Electronic address: amdurr@shands.ufl.edu.
Abstract
PURPOSE: To determine if whole-neck intensity-modulated radiotherapy (IMRT) spares the larynx as well as techniques that match a conventional anterior-neck field to an IMRT plan superior to the larynx. METHODS AND MATERIALS: This is a dosimetric study using the treatment planning image sets from 5 consecutively treated patients with node-positive squamous cell carcinoma of the oropharynx, all with gross disease above the larynx. We compared 3 techniques for irradiating the mid- and low-neck lymphatics: whole-neck IMRT, conventional anterior-neck field with split-beam matching, and conventional anterior-neck field with gradient matching. Prescription doses for the high-, intermediate-, and standard-risk planning target volumes were 70 Gy, 60 Gy, and 50 Gy, respectively. RESULTS: The mean larynx dose was similar with all techniques with median values: whole-neck IMRT, 28 Gy (range, 17-30 Gy); conventional field with split-beam matching, 26 Gy (range, 21-33 Gy); conventional field with gradient matching, 30 Gy (range, 25-31 Gy). CONCLUSIONS: With meticulous attention to the details of contouring and treatment planning, it is possible to use whole-neck IMRT without increasing the risk of larynx dysfunction compared to techniques that block the larynx in a conventional anterior-neck field. We discuss the potential advantages of each technique in this article.
PURPOSE: To determine if whole-neck intensity-modulated radiotherapy (IMRT) spares the larynx as well as techniques that match a conventional anterior-neck field to an IMRT plan superior to the larynx. METHODS AND MATERIALS: This is a dosimetric study using the treatment planning image sets from 5 consecutively treated patients with node-positive squamous cell carcinoma of the oropharynx, all with gross disease above the larynx. We compared 3 techniques for irradiating the mid- and low-neck lymphatics: whole-neck IMRT, conventional anterior-neck field with split-beam matching, and conventional anterior-neck field with gradient matching. Prescription doses for the high-, intermediate-, and standard-risk planning target volumes were 70 Gy, 60 Gy, and 50 Gy, respectively. RESULTS: The mean larynx dose was similar with all techniques with median values: whole-neck IMRT, 28 Gy (range, 17-30 Gy); conventional field with split-beam matching, 26 Gy (range, 21-33 Gy); conventional field with gradient matching, 30 Gy (range, 25-31 Gy). CONCLUSIONS: With meticulous attention to the details of contouring and treatment planning, it is possible to use whole-neck IMRT without increasing the risk of larynx dysfunction compared to techniques that block the larynx in a conventional anterior-neck field. We discuss the potential advantages of each technique in this article.
Authors: Yanqun Dong; John A Ridge; Tianyu Li; Miriam N Lango; Thomas M Churilla; Jessica R Bauman; Thomas J Galloway Journal: Oral Oncol Date: 2017-06-23 Impact factor: 5.337