Abstract

Background: The risk of second primary malignancies (SPMs) associated with cancer therapies is an important concern of thyroid cancer survivors and physicians. Our objective was to determine if the risk of SPMs is increased in individuals with thyroid cancer treated with radioactive iodine (RAI), compared to those not treated with RAI.
Methods: We performed a systematic review of the literature and meta-analysis. Two independent reviewers screened citations and reviewed full-text papers. If not reported by the primary authors, the relative risk (RR) of SPMs was calculated by dividing the standardized incidence ratio of SPM in individuals with thyroid cancer treated with RAI compared to those not treated with RAI (with associated 95% confidence intervals [CI]). The natural logarithms of RRs of respective SPMs, weighted by the inverse of the variance, were pooled using fixed effects models and the exponential of the results was reported.
Results: Two multi-center studies (one from Europe and the other from North America) were included in this review. The RR of SPMs in thyroid cancer survivors treated with RAI was significantly increased at 1.19 (95% confidence interval [CI] 1.04, 1.36, p = 0.010), relative to thyroid cancer survivors not treated with RAI (data from 16,502 individuals), using a minimum latency period of 2 to 3 years after thyroid cancer diagnosis. The RR of leukemia was also significantly increased in thyroid cancer survivors treated with RAI, with an RR of 2.5 (95% CI 1.13, 5.53, p = 0.024). We did not observe a significantly increased risk of the following cancers related to prior RAI treatment: bladder, breast, central nervous system, colon and rectum, digestive tract, stomach, pancreas, kidney (and renal pelvis), lung, or melanoma of skin.
Conclusions: The risk of SPMs in thyroid cancer survivors treated with RAI is slightly increased compared to thyroid cancer survivors not treated with RAI.

Formats available

You can view the full content in the following formats:

Information & Authors

Information

Published In

cover image Thyroid®
Thyroid
Volume 19Issue Number 5May 2009
Pages: 451 - 457
PubMed: 19281429

History

Published online: 5 May 2009
Published in print: May 2009
Published ahead of print: 13 March 2009

Permissions

Request permissions for this article.

Topics

Authors

Affiliations

Anna M. Sawka, M.D., Ph.D., FRCPC
Division of Endocrinology and Department of Medicine, University Health Network, Toronto, Ontario, Canada.
Division of Endocrinology and Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Lehana Thabane, Ph.D.
Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.
Centre for Evaluation of Medicines, St. Joseph's Healthcare, Hamilton, Ontario, Canada.
Luciana Parlea, M.D.
Division of Endocrinology and Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Irada Ibrahim-Zada, M.D.
Division of Endocrinology, Department of Medicine, University Health Network, Toronto, Ontario, Canada.
Richard W. Tsang, M.D., FRCPC
Department of Radiation Oncology, University Health Network and University of Toronto, Toronto, Ontario, Canada.
James D. Brierley, M.D., FRCPC
Department of Radiation Oncology, University Health Network and University of Toronto, Toronto, Ontario, Canada.
Sharon Straus, M.D., FRCPC, M.Sc.
Department of Knowledge Translation, University of Toronto, Ontario, Canada.
Shereen Ezzat, M.D.
Division of Endocrinology and Department of Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada.
The Freeman Centre for Endocrine Oncology, Toronto, Ontario, Canada.
The Ontario Cancer Institute, Toronto, Ontario, Canada.
David P. Goldstein, M.D., FRCSC
Department of Surgery, University Health Network and University of Toronto, Toronto, Ontario, Canada.
Department of Otolaryngology Head and Neck Surgery, University Health Network and University of Toronto, Toronto, Ontario, Canada.

Notes

Address reprint requests to:
Anna M. Sawka, M.D., Ph.D., FRCPC
Toronto General Hospital
200 Elizabeth St.
Eaton North 12-212
Toronto, Ontario, M5G 2C4
Canada
E-mail: [email protected]

Metrics & Citations

Metrics

Citations

Export citation

Select the format you want to export the citations of this publication.

View Options

View options

PDF/EPUB

View PDF/ePub

Get Access

Access content

To read the fulltext, please use one of the options below to sign in or purchase access.

Society Access

If you are a member of a society that has access to this content please log in via your society website and then return to this publication.

Restore your content access

Enter your email address to restore your content access:

Note: This functionality works only for purchases done as a guest. If you already have an account, log in to access the content to which you are entitled.

Media

Figures

Other

Tables

Share

Share

Copy the content Link

Share on social media

Back to Top