In our view, there is little doubt that use of recombinant human thyrotropin (rhTSH) has proved of significant benefit to patients with low- or intermediate-risk differentiated thyroid cancer (DTC). And in their communication regarding our study [1], Zandee and Links [2] present compelling arguments with which we fully agree on the importance and merits of also establishing that preparation by rhTSH for radioiodine (RAI) therapy of higher risk or metastatic DTC would be equally efficacious to preparation by thyroid hormone withdrawal. Insofar as our study did reach this conclusion, they express concern that we may have overstated that the results achieved by the 2 approaches were equivalent due to underpowering of the study. While our conclusions are supported by prior analyses as cited in our paper [3, 4], Zandee and Links [2] indicate that perhaps due to the multifarious nature of factors influencing thyroid cancer survival (in our subjects and presumably in general) that the failure to observe a statistically significant difference between the outcomes derived from the 2 approaches does not signify that they can be considered equivalent. While this inference is arguable, in our view it renders any conclusion inutile or ambiguous. Our cautionary conclusion was that the choice of preparation for RAI would not “decisively affect outcome” because outcomes in the 2 groups of patients did not significantly differ statistically. We acknowledged multiple potential shortcomings of our study including the number of patients, duration of follow-up, selection bias, and retrospective design, and, as do Zandee and Links [2], look to the need for a perhaps international, carefully controlled larger study to more definitively resolve this question. Until such confirmatory data are available, we are comfortable continuing to offer the option of rhTSH preparation for RAI therapy to our patients with metastatic disease, with or without dosimetry, taking into account multiple factors known to influence either adverse or beneficial aspects of RAI therapy on an individual, personalized basis.
Abbreviations
- DTC
differentiated thyroid cancer
- RAI
radioiodine
- rhTSH
recombinant human thyrotropin
Contributor Information
Cristiane J Gomes-Lima, Email: cjglima@gmail.com, MedStar Clinical Research Center, MedStar Health Research Institute (MHRI), Hyattsville, MD 20782-2031, USA; Section of Endocrinology, MedStar Washington Hospital Center, Washington, DC 20010, USA.
Sanjita Chittimoju, Department of Internal Medicine, MedStar Washington Hospital Center, Washington, DC 20010, USA.
Leen Wehbeh, Department of Internal Medicine, MedStar Washington Hospital Center, Washington, DC 20010, USA.
Sunita Dia, Department of Internal Medicine, MedStar Washington Hospital Center, Washington, DC 20010, USA.
Prathyusha Pagadala, Department of Internal Medicine, MedStar Washington Hospital Center, Washington, DC 20010, USA.
Mohammad Al-Jundi, Department of Internal Medicine, MedStar Washington Hospital Center, Washington, DC 20010, USA.
Sakshi Jhawar, Department of Internal Medicine, Sinai Hospital of Baltimore, Research Volunteer, Baltimore, MD 21215, USA.
Eshetu Tefera, Department of Biostatistics, MedStar Health Research Institute (MHRI), Hyattsville, MD 20782-2031, USA.
Mihriye Mete, Department of Biostatistics, MedStar Health Research Institute (MHRI), Hyattsville, MD 20782-2031, USA.
Joanna Klubo-Gwiezdzinska, Thyroid Tumors and Functional Thyroid Disorders Section, National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Diseases (NIH/NIDDK), Bethesda, MD 20892, USA.
Douglas Van Nostrand, MedStar Clinical Research Center, MedStar Health Research Institute (MHRI), Hyattsville, MD 20782-2031, USA; Nuclear Medicine Research, MedStar Washington Hospital Center, Washington, DC 20010, USA.
Jacqueline Jonklaas, Division of Endocrinology, Department of Medicine, Georgetown University, Washington, DC 20057, USA.
Leonard Wartofsky, Section of Endocrinology, MedStar Washington Hospital Center, Washington, DC 20010, USA.
Kenneth D Burman, Section of Endocrinology, MedStar Washington Hospital Center, Washington, DC 20010, USA; Division of Endocrinology, Department of Medicine, Georgetown University, Washington, DC 20057, USA.
Disclosures
D.V.N.: speaker and consultant for Jubilant DraxImage. No competing financial interests exist for the remaining authors.
References
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