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Journal of Thyroid Research
Volume 2010, Article ID 183461, 7 pages
Clinical Study

Differentiated Thyroid Cancer with Extrathyroidal Extension: Prognosis and the Role of External Beam Radiotherapy

1Department of Radiation Oncology, Tom Baker Cancer Centre, Calgary, AB, Canada T2N 4N2
2Department of Radiation Oncology, University of Calgary, Calgary, AB, Canada T2N 4N1
3Department of Radiation Oncology, Princess Margaret Hospital, Toronto, ON, Canada M5G 2M9
4Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada M5S 3E2
5Department of Biostatistics, Princess Margaret Hospital, University of Toronto, Toronto, ON, Canada M5S 2M9
6Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada M5T 3M7

Received 3 July 2009; Accepted 2 March 2010

Academic Editor: Jeremy L. Freeman

Copyright © 2010 Michael A. Sia et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A study was performed to identify variables that affected cause-specific survival (CSS) and local relapse-free rate (LRFR) in patients with differentiated thyroid cancer (DTC) and extrathyroid extension (ETE) and to examine the role of external beam radiotherapy (XRT). Prognostic factors were similar to those found in studies of all patients with DTC. In patients with postoperative gross residual disease treated with radiotherapy, 10-year CSS and LRFR were 48% and 90%. For patients with no residual or microscopic disease, 10-year CSS and LRFR were 92% and 93%. In patients older than 60 years with T3 ETE but no gross residual disease postoperatively there was an improved LRFR at 5 years of 96%, compared to 87.5% without XRT ( 𝑃 = . 0 2 ). Patients with gross ETE benefit from XRT and there may be a potential benefit in reducing locoregional failure in patients over 60 years with minimal extrathyroidal extension (T3).