| Pre-treatment number of clonogenic cells and their radiosensitivity are major determinants of local tumour control after fractionated irradiation. | |
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MedLine Citation:
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PMID: 17517444 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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OBJECTIVE: The response of tumours to fractionated radiotherapy is determined by many factors including repopulation, reoxygenation, the number of clonogenic cells, and their intrinsic radiosensitivity. However, after single radiation doses given under conditions of clamp hypoxia, the dose to control a tumour locally is dependent only on the number of clonogenic cells and their cellular radiosensitivity. Therefore, these parameters were investigated using local control after single doses given under hypoxia, to predict the outcome of fractionated irradiation. MATERIALS AND METHODS: Ten hSCC cell lines (FaDu, UT-SCC-15, UT-SCC-14, XF354, UT-SCC-5, UT-SCC-45, SAS, CAL-33, UT-SCC-8, and HSC-4) were transplanted subcutaneously into the right hind-leg of NMRI nude mice. At 7mm in diameter, tumours were irradiated either with graded single doses under clamp blood flow conditions (n=873) or with 30 graded fractions within 6 weeks (n=905) under ambient conditions. Local tumour control was determined 120 days after irradiation. Radiation response was quantified in terms of TCD(50), i.e. the dose required to control 50% of tumours locally. RESULTS: Ten tumour lines investigated showed a pronounced heterogeneity in both TCD(50(30fx/6w)) after fractionated irradiation and TCD(50(SDclamp)) after single dose irradiation. TCD(50(30fx/6w)) varied between 45Gy for UT-SCC-45 and 127Gy for SAS; TCD(50(SDclamp)) varied between 42Gy for UT-SCC-14 and 66Gy for CAL-33. Two tumours were excluded from further analysis due to immunogenicity or non-defined TCD(50). Linear regression analysis revealed a significant positive correlation between TCD(50(SDclamp)) and TCD(50(30fx/6w)) (R(2)=0.82, p=0.002). CONCLUSIONS: Significant association between TCD(50(SDclamp)) and TCD(50(30fx/6w)) suggests that the pre-treatment number of clonogenic tumour cells and their cellular radiosensitivity have a major impact on local control after fractionated radiotherapy. |
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Authors:
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Ala Yaromina; Marie Krause; Howard Thames; Andrea Rosner; Mechthild Krause; Franziska Hessel; Reidar Grenman; Daniel Zips; Michael Baumann |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2007-05-22 |
Journal Detail:
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Title: Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology Volume: 83 ISSN: 0167-8140 ISO Abbreviation: Radiother Oncol Publication Date: 2007 Jun |
Date Detail:
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Created Date: 2007-06-20 Completed Date: 2008-03-13 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8407192 Medline TA: Radiother Oncol Country: Ireland |
Other Details:
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Languages: eng Pagination: 304-10 Citation Subset: IM |
Affiliation:
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OncoRay - Centre for Radiation Research in Oncology, University of Technology Dresden, Germany. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Carcinoma, Squamous Cell / radiotherapy* Cell Count Cell Hypoxia Clone Cells / radiation effects* Dose Fractionation* Dose-Response Relationship, Radiation Female Head and Neck Neoplasms / radiotherapy* Humans Male Mice Mice, Nude Neoplasm Recurrence, Local / prevention & control* Radiation Tolerance* Tumor Stem Cell Assay Xenograft Model Antitumor Assays |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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