Methods for estimating the site of origin of locoregional recurrence in head and neck squamous cell carcinoma.
Strahlenther Onkol
; 188(8): 671-6, 2012 Aug.
Article
em En
| MEDLINE
| ID: mdl-22580623
ABSTRACT
PURPOSE:
Methods to estimate the likely origin of recurrences after radiation therapy for head and neck squamous cell carcinoma are compared. METHODS AND MATERIALS A total of 25 patients meeting the following inclusion criteria were randomly selected curatively intended intensity-modulated radiotherapy planned on a positron emission tomography-computed tomography (PET/CT) scan during the period 2005-2009; squamous cell carcinoma in the oral cavity, pharynx or larynx; complete clinical response followed by locoregional recurrence; and a CT scan at recurrence before any salvage therapy. Exclusion criteria were previous cancer in the area, surgery prior to radiotherapy, or a synchronous cancer. Three methods of estimating focal points of recurrence origin and two volume overlap methods assigning the recurrences to the most central target volumes encompassing at least 50% or 95% of the recurrence volumes were tested. Treatment planning and recurrence scans were rigid and deformable co-registered in order to transfer focal points to the treatment planning scan. Double determinations of all volumes, points, and co-registrations were made.RESULTS:
The volume overlap methods assigned the recurrences to significantly more peripheral target volumes than focal methods (p < 0.0001 for all comparisons of 95% overlap vs. focal methods, p < 0.028 for all comparisons of 50% overlap vs. focal methods). Repeated registrations of the same point had higher reproducibility with deformable registration than with rigid registration (median distance 0.31 vs. 0.35 cm, p = 0.015). No significant differences were observed among the focal methods.CONCLUSION:
Significant differences between methods were found which may affect strategies to improve radiotherapy based on pattern of failure analyses.
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MEDLINE
Assunto principal:
Neoplasias Primárias Desconhecidas
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Planejamento da Radioterapia Assistida por Computador
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Neoplasias Otorrinolaringológicas
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Carcinoma de Células Escamosas
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Radioterapia de Intensidade Modulada
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Neoplasias de Cabeça e Pescoço
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Recidiva Local de Neoplasia
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article