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Insular thyroid cancer
A population-level analysis of patient characteristics and predictors of survival
Article first published online: 17 JAN 2012
Copyright © 2011 American Cancer Society
Volume 118, Issue 13, pages 3260–3267, 1 July 2012
How to Cite
Kazaure, H. S., Roman, S. A. and Sosa, J. A. (2012), Insular thyroid cancer. Cancer, 118: 3260–3267. doi: 10.1002/cncr.26638
A portion of these data were presented as a poster at the American Thyroid Association meeting, October 26-30, 2011, Indian Wells, CA
- Issue published online: 18 JUN 2012
- Article first published online: 17 JAN 2012
- Manuscript Accepted: 16 SEP 2011
- Manuscript Revised: 15 SEP 2011
- Manuscript Received: 20 JUL 2011
- thyroid cancer;
- Surveillance, Epidemiology, and End Results;
- poorly differentiated;
- intermediately differentiated;
- well differentiated
Insular thyroid cancer (ITC) is an uncommon, poorly differentiated thyroid malignancy. To date, there have been no population-level studies of the characteristics and outcomes of patients with ITC.
The authors used the Surveillance, Epidemiology, and End Results (SEER) database from 1999 to 2007 to compare the characteristics and prognosis of patients who had ITC with those of patients who had well differentiated thyroid cancer (WDTC) and anaplastic thyroid cancer (ATC). Data analyses were performed using chi-square tests, analyses of variance, log-rank tests, and multivariate regression.
There were 114 patients with ITC, 497 patients with ATC, and 34,021 patients with WDTC. The mean age of patients with ITC was 62.1 years versus 48.1 years for patients with WDTC and 69.5 years for patients with ATC (P < .001). The mean ITC tumor size was 5.9 cm versus 2.0 cm for WDTC and 6.4 cm for ATC (P < .001). Distant metastasis occurred in 31% of patients with ITC versus 4.5% of patients with WDTC and 59.1% of patients with ATC (P < .001). Insular histology was associated independently with compromised survival in the overall study sample (hazard ratio [HR], 2.1; P = .001). The 5-year disease-specific survival rate was 72.6%, 97.2%, and 9.1% for patients with ITC, WDTC, and ATC, respectively (P < .001). After adjustment, radioiodine therapy (HR, 0.15; 95% confidence interval, 0.04-0.5) and distant metastasis (HR, 15.3; 95% confidence interval, 3.7-62.2) were associated independently with ITC survival. The mortality rate was 7.1%, 12%, and 54.3% for patients with localized, regional, and distant stage ITC, respectively (P < .001). For patients who had ITC with distant metastasis, thyroidectomy and radioiodine therapy independently improved survival.
ITC is rare and aggressive. The current results indicated that its treatment should include total thyroidectomy and high-dose radioiodine for all patients and neck dissections for patients with lymph node disease. Early diagnosis and close surveillance are essential in the management of patients with ITC. Cancer 2011. © 2011 American Cancer Society.