Biomaterial Database

Parotid gland function after radiotherapy: the combined michigan and utrecht experience. 2010

Tim Dijkema, and Cornelis P J Raaijmakers, and Randall K Ten Haken, and Judith M Roesink, and Pètra M Braam, and Anette C Houweling, and Marinus A Moerland, and Avraham Eisbruch, and Chris H J Terhaard

Department of Radiotherapy, University Medical Center Utrecht, The Netherlands. T.Dijkema@umcutrecht.nl

OBJECTIVE To analyze the combined and updated results from the University of Michigan and University Medical Center Utrecht on normal tissue complication probability (NTCP) of the parotid gland 1 year after radiotherapy (RT) for head-and-neck (HN) cancer. METHODS A total of 222 prospectively analyzed patients with various HN malignancies were treated with conventional and intensity-modulated RT. Stimulated individual parotid gland flow rates were measured before RT and 1 year after RT using Lashley cups at both centers. A flow ratio <25% of pretreatment was defined as a complication. The data were fitted to the Lyman-Kutcher-Burman model. RESULTS A total of 384 parotid glands (Michigan: 157; Utrecht: 227 glands) was available for analysis 1 year after RT. Combined NTCP analysis based on mean dose resulted in a TD(50) (uniform dose leading to 50% complication probability) of 39.9 Gy and m (steepness of the curve) of 0.40. The resulting NTCP curve had good qualitative agreement with the combined clinical data. Mean doses of 25-30 Gy were associated with 17-26% NTCP. CONCLUSIONS A definite NTCP curve for parotid gland function 1 year after RT is presented, based on mean dose. No threshold dose was observed, and TD(50) was equal to 40 Gy.

UI	MeSH Term	Description	Entries
D007928	Lethal Dose 50	The dose amount of poisonous or toxic substance or dose of ionizing radiation required to kill 50% of the tested population.	LD50,Dose 50, Lethal
D008297	Male		Males
D008824	Michigan	State bounded on the north by the Great Lakes, on the east by Canada, on the south by Wisconsin, Indiana, and Ohio, and on the west by Lake Michigan and Wisconsin.
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D009426	Netherlands	Country located in EUROPE. It is bordered by the NORTH SEA, BELGIUM, and GERMANY. Constituent areas are Aruba, Curacao, and Sint Maarten, formerly included in the NETHERLANDS ANTILLES.	Holland,Kingdom of the Netherlands
D010306	Parotid Gland	The largest of the three pairs of SALIVARY GLANDS. They lie on the sides of the FACE immediately below and in front of the EAR.	Gland, Parotid,Glands, Parotid,Parotid Glands
D011446	Prospective Studies	Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.	Prospective Study,Studies, Prospective,Study, Prospective
D004307	Dose-Response Relationship, Radiation	The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.	Dose Response Relationship, Radiation,Dose-Response Relationships, Radiation,Radiation Dose-Response Relationship,Radiation Dose-Response Relationships,Relationship, Radiation Dose-Response,Relationships, Radiation Dose-Response
D005260	Female		Females