title: Intensity-modulated proton beam therapy (IMPT) versus intensity-modulated photon therapy (IMRT) for patients with oropharynx cancer - A case matched analysis.
abstract: Owing to its physical properties, intensity-modulated proton therapy (IMPT) used for patients with oropharyngeal carcinoma has the ability to reduce the dose to organs at risk compared to intensity-modulated radiotherapy (IMRT) while maintaining adequate tumor coverage. Our aim was to compare the clinical outcomes of these two treatment modalities.
  
  
  
  We performed a 1:2 matching of IMPT to IMRT patients. Our study cohort consisted of IMPT patients from a prospective quality of life study and consecutive IMRT patients treated at a single institution during the period 2010-2014. Patients were matched on unilateral/bilateral treatment, disease site, human papillomavirus status, T and N status, smoking status, and receipt of concomitant chemotherapy. Survival analyzes were performed using a Cox model and binary toxicity endpoints using a logistic regression analysis.
  
  
  
  Fifty IMPT and 100 IMRT patients were included. The median follow-up time was 32months. There were no imbalances in patient/tumor characteristics except for age (mean age 56.8years for IMRT patients and 61.1years for IMPT patients, p-value=0.010). Statistically significant differences were not observed in overall survival (hazard ratio (HR)=0.55; 95% confidence interval (CI): 0.12-2.50, p-value=0.44) or in progression-free survival (HR=1.02; 95% CI: 0.41-2.54; p-value=0.96). The age-adjusted odds ratio (OR) for the presence of a gastrostomy (G)-tube during treatment for IMPT vs IMRT were OR=0.53; 95% CI: 0.24-1.15; p-value=0.11 and OR=0.43; 95% CI: 0.16-1.17; p-value=0.10 at 3months after treatment. When considering the pre-planned composite endpoint of grade 3 weight loss or G-tube presence, the ORs were OR=0.44; 95% CI: 0.19-1.0; p-value=0.05 at 3months after treatment and OR=0.23; 95% CI: 0.07-0.73; p-value=0.01 at 1year after treatment.
  
  
  
  Our results suggest that IMPT is associated with reduced rates of feeding tube dependency and severe weight loss without jeopardizing outcome. Prospective multicenter randomized trials are needed to validate such findings.
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA; Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Blanchard
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: Adam S
authors.initials: AS
authors.lastname: Garden
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: G Brandon
authors.initials: GB
authors.lastname: Gunn
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: David I
authors.initials: DI
authors.lastname: Rosenthal
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: William H
authors.initials: WH
authors.lastname: Morrison
authors.affiliation: Department of Quantitative Sciences, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: Mike
authors.initials: M
authors.lastname: Hernandez
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Crutison
authors.affiliation: Department of Quantitative Sciences, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: Jack J
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Department of Quantitative Sciences, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Ye
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA; Medical Physics Program, The University of Texas Graduate School of Biomedical Sciences, Houston, USA.
authors.forename: C David
authors.initials: CD
authors.lastname: Fuller
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA; Department of Clinical Oncology and Nuclear Medicine, University of Alexandria, Egypt.
authors.forename: Abdallah S R
authors.initials: AS
authors.lastname: Mohamed
authors.affiliation: Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: Kate A
authors.initials: KA
authors.lastname: Hutcheson
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: Emma B
authors.initials: EB
authors.lastname: Holliday
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: Nikhil G
authors.initials: NG
authors.lastname: Thaker
authors.affiliation: Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: Erich M
authors.initials: EM
authors.lastname: Sturgis
authors.affiliation: Department of Thoracic/Head & Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: Merrill S
authors.initials: MS
authors.lastname: Kies
authors.affiliation: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: X Ronald
authors.initials: XR
authors.lastname: Zhu
authors.affiliation: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors.forename: Radhe
authors.initials: R
authors.lastname: Mohan
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA. Electronic address: sjfrank@mdanderson.org.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Frank
mesh_terms: D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D004750:Enteral Nutrition; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009959:Oropharyngeal Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D061766:Proton Therapy / Q000379:methods*; D011788:Quality of Life; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*
keywords: Chemoradiation; Human papilloma virus; Intensity-modulated proton therapy; Intensity-modulated radiotherapy; Oropharyngeal cancer; Radiation therapy