title: Esophageal tolerance to high-dose stereotactic ablative radiotherapy.
abstract: Dose-volume parameters are needed to guide the safe administration of stereotactic ablative radiotherapy (SABR). We report on esophageal tolerance to high-dose hypofractionated radiation in patients treated with SABR. Thirty-one patients with spine or lung tumors received single- or multiple-fraction SABR to targets less than 1 cm from the esophagus. End points evaluated include D(5cc) (minimum dose in Gy to 5 cm(3) of the esophagus receiving the highest dose), D(2cc) , D(1cc) , and D(max) (maximum dose to 0.01 cm(3) ). Multiple-fraction treatments were correlated using the linear quadratic and linear quadratic-linear/universal survival models. Three esophageal toxicity events occurred, including esophagitis (grade 2), tracheoesophageal fistula (grade 4-5), and esophageal perforation (grade 4-5). Chemotherapy was a cofactor in the high-grade events. The median time to development of esophageal toxicity was 4.1 months (range 0.6-6.1 months). Two of the three events occurred below a published D(5cc) threshold, all three were below a D(2cc) threshold, and one was below a D(max) threshold. We report a dosimetric analysis of incidental dose to the esophagus from SABR. High-dose hypofractionated radiotherapy led to a number of high-grade esophageal adverse events, suggesting that conservative parameters to protect the esophagus are necessary when SABR is used, especially in the setting of chemotherapy or prior radiotherapy.
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305-5847, USA. jonabelson@gmail.com
authors.forename: J A
authors.initials: JA
authors.lastname: Abelson
authors.forename: J D
authors.initials: JD
authors.lastname: Murphy
authors.forename: B W
authors.initials: BW
authors.lastname: Loo
authors.forename: D T
authors.initials: DT
authors.lastname: Chang
authors.forename: M E
authors.initials: ME
authors.lastname: Daly
authors.forename: E A
authors.initials: EA
authors.lastname: Wiegner
authors.forename: S
authors.initials: S
authors.lastname: Hancock
authors.forename: S D
authors.initials: SD
authors.lastname: Chang
authors.forename: Q-T
authors.initials: QT
authors.lastname: Le
authors.forename: S G
authors.initials: SG
authors.lastname: Soltys
authors.forename: I C
authors.initials: IC
authors.lastname: Gibbs
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004939:Esophageal Perforation / Q000209:etiology; D004941:Esophagitis / Q000209:etiology; D004947:Esophagus / Q000528:radiation effects*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000009:adverse effects*; D012189:Retrospective Studies; D013125:Spinal Neoplasms / Q000601:surgery*; D013997:Time Factors; D014138:Tracheoesophageal Fistula / Q000209:etiology