Model-based calculation of thyroid gland normal tissue complication probability in head and neck cancer patients after radiation therapy.
Strahlenther Onkol
; 196(6): 561-568, 2020 Jun.
Article
en En
| MEDLINE
| ID: mdl-32016495
ABSTRACT
AIM:
Primary hypothyroidism is one of the late complications that can occur after radiation therapy for malignant tumors in the head and neck region. The aim of this retrospective study was to show the validity of the Lyman-Kutcher-Burman (LKB) normal tissue complication model for thyroid gland based on clinical results.METHODS:
Thyroid function was evaluated by measuring thyroid-stimulating hormone and free thyroxine serum levels before radiation therapy, 3 months after the beginning of radiation therapy, and afterwards at each follow-up visit. Cumulative incidence was calculated using the Kaplan-Meier method. Dose-volume histogram, total dose, fractionation schedule, total duration of the treatment, and other parameters were used for normal tissue complication probability calculation based on the LKB model. The model was evaluated after fitting with the three sets of parameters for grade 2 hypothyroidism 1) "Emami," where nâ¯= 0.22; mâ¯= 0.26, and D50â¯= 80â¯Gy; 2) "mean dose," where nâ¯= 1; mâ¯= 0.27, and D50â¯= 60â¯Gy; and 3) "Lyman EUD," where nâ¯= 0.49; mâ¯= 0.24, and D50â¯= 60â¯Gy. A value 3.0â¯Gy was used for α/ß ratioRESULTS:
Eighty-three patients treated with volumetric modulated arc therapy for head and neck cancers at the University Hospital Martin, Slovakia, from January 2014 to July 2017, were included in the retrospective study. Median follow-up was 1.2 years. Cumulative incidence of hypothyroidism grade 2 or higher after 12 and 24 months was 9.6 and 22.0%, respectively. Normal tissue complication probability values calculated with mean dose and Lyman EUD parameters showed the best correlation with our clinical findings.CONCLUSION:
Empirically based modelling of normal tissue complication probability was valid for our cohort of patients. With carefully chosen parameters, the LKB model can be used for predicting the normal tissue complication probability value.Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Traumatismos por Radiación
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Glándula Tiroides
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Carcinoma de Células Escamosas
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Radioterapia de Intensidad Modulada
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Órganos en Riesgo
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Neoplasias de Cabeza y Cuello
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Hipotiroidismo
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Modelos Biológicos
Tipo de estudio:
Etiology_studies
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Incidence_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Límite:
Adult
/
Aged
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Female
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Humans
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Male
/
Middle aged
Idioma:
En
Revista:
Strahlenther Onkol
Asunto de la revista:
NEOPLASIAS
/
RADIOTERAPIA
Año:
2020
Tipo del documento:
Article
País de afiliación:
Eslovaquia