Phantom-to-clinic development of hypofractionated stereotactic body radiotherapy for early-stage glottic laryngeal cancer

Chuxiong Ding; Stephen G Chun; Baran D Sumer; Lucien A Nedzi; Ramzi E Abdulrahman; John S Yordy; Pam Lee; Brian Hrycushko; Timothy D Solberg; Chul Ahn; Robert D Timmerman; David L Schwartz

doi:10.1016/j.meddos.2017.01.004

Phantom-to-clinic development of hypofractionated stereotactic body radiotherapy for early-stage glottic laryngeal cancer

Med Dosim. 2017;42(2):90-96. doi: 10.1016/j.meddos.2017.01.004. Epub 2017 Apr 21.

Authors

Affiliations

¹ Department of Radiation Oncology, Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX.
² Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX.
³ Department of Otolaryngology, University of Texas Southwestern Medical Center, Dallas, TX.
⁴ Valley Radiation Therapy Center, Anchorage, AK.
⁵ Department of Radiation Oncology, Abramson Comprehensive Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
⁶ Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX.
⁷ Department of Radiation Oncology, Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX. Electronic address: david.schwartz214@gmail.com.

PMID: 28438431
DOI: 10.1016/j.meddos.2017.01.004

Abstract

The purpose of this study was to commission and clinically test a robotic stereotactic delivery system (CyberKnife, Sunnyvale, CA) to treat early-stage glottic laryngeal cancer. We enrolled 15 patients with cTis-T2N0M0 carcinoma of the glottic larynx onto an institutional review board (IRB)-approved clinical trial. Stereotactic body radiotherapy (SBRT) plans prescribed 45 Gy/10 fractions to the involved hemilarynx. SBRT dosimetry was compared with (1) standard carotid-sparing laryngeal intensity-modulated radiation therapy (IMRT) and (2) selective hemilaryngeal IMRT. Our results demonstrate that SBRT plans improved sparing of the contralateral arytenoid (mean 20.0 Gy reduction, p <0.001), ipsilateral carotid D_max (mean 20.6 Gy reduction, p <0.001), contralateral carotid D_max (mean 28.1 Gy reduction, p <0.001), and thyroid D_mean (mean 15.0 Gy reduction, p <0.001) relative to carotid-sparing IMRT. SBRT also modestly improved dose sparing to the contralateral arytenoid (mean 4.8 Gy reduction, p = 0.13) and spinal cord D_max (mean 4.9 Gy reduction, p = 0.015) relative to selective hemilaryngeal IMRT plans. This "phantom-to-clinic" feasibility study confirmed that hypofractionated SBRT treatment for early-stage laryngeal cancer can potentially spare dose to adjacent normal tissues relative to current IMRT standards. Clinical efficacy and toxicity correlates continue to be collected through an ongoing prospective trial.

Keywords: CyberKnife; Laryngeal cancer; Phantom; SBRT.

Publication types

Clinical Trial

MeSH terms

Aged
Female
Glottis / pathology*
Humans
Laryngeal Neoplasms / pathology*
Laryngeal Neoplasms / radiotherapy*
Male
Middle Aged
Neoplasm Staging
Organ Sparing Treatments / methods
Phantoms, Imaging
Radiation Dose Hypofractionation*
Radiosurgery / methods*
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted / methods*
Radiotherapy, Image-Guided / methods*
Reproducibility of Results
Sensitivity and Specificity
Treatment Outcome