Abstracts - Orals, Featured Poster Presentations, and Posters
SUN 459-496-Thyroid Neoplasia & Case Reports
Expo Halls ABC (Moscone Center)
Poster Board SUN-468
: Early investigations using rhTSH preparation for radioiodine whole-body scintigraphy (WBS) in evaluation of thyroid cancer patients revealed pitfalls in: timing of rhTSH injections & thyroglobulin (Tg) measurement, magnitude of radioiodine dose, and WBS techniques (1, 2); causing false-negative studies. These resulted in FDA and manufacturer guidelines (3) that emulate methodology (RcmPrtcl) verified by Haugen et al (4). RcmPrtcl entails a preceding low-iodine diet (LID), 2 injections of rhTSH (Day 1 & Day 2), ≥4 mCi (148 MBq) NaI-131 tracer on Day 3, and WBS & Tg measurement on Day 5. RcmPrtcl scanning parameters are: WBS acquired ≥30 min &/or containing ≥140,000 counts, spot images for 10-15 min or ≥60,000 counts (large field of view camera) or ≥35,000 counts (small field of view). For NaI-123 doses, WBS occurs on Day 4. Compliance with RcmPrtcl methods was assessed from data acquired by survey of nuclear medicine technologist (NMT) members of Society of Nuclear Medicine and Molecular Imaging (SNMMI).
Methods: An IRB-approved web-based survey, using Qualtrics® software, was provided to 9,172 NMTs contacted by emails from SNMMI sent thrice (q 2 weeks: 9/12/12 – 10/11/12). 1,385 surveys were received with 501 sufficiently complete for analysis. Surveys were sorted by stated nuclear medicine facility (NMF) or IP address if unclear. The single most-complete of multiple surveys from same NMF was used, resulting in complete surveys from 366 distinct NMFs. Surveys of 190 NMFs (62%) who used rhTSH for ≥20% of their WBSs were further analyzed.
Results: Only 5 of 190 NMFs (3%) used the entire RcmPrtcl (aside from LID use) but only 1 of these used a LID (0.5%). Although 28 NMFs (15%) used a LID & ≥4 mCi NaI-131 dose, they did not use advised higher count acquisition/scan times. Common deviations included: obtaining Tg on Day 3 instead of Day 5 (7%), obtaining Tg and the scan on Day 4 (2%), and not obtaining Tg assessments at all (13%). 4 NMF’s (2%), gave rhTSH on Days 1 & 2, but prematurely gave NaI-123 tracer on Day 2. Although 3% of NMFs used LID & proper scanning/scan-dose parameters, rhTSH was not administered according to RcmPrtcl. The majority of NMFs failed to follow multiple aspects of RcmPrtcl.
Conclusions: Although carefully executed clinical trials have been the basis for guidelines regarding rhTSH-prepped radioiodine WBS, the actual clinical performance does not meet established standards, resulting in significant risk of false-negative evaluations, both in imaging and Tg assessments. Considering the slow progression of differentiated thyroid cancers, consequences of these deficiencies would not be evident in the few years of follow-up reported in currently published studies. Reasons for non-adherence to RcmPrtcl are not known, but include lack of knowledge or understanding and economic disincentives.
(1). Ladenson PW, Braverman LE, Mazzaferri EL, Brucker-Davis F, Cooper DS, Garber JR, Wondisford FE, Davies TF, DeGroot LJ, Daniels GH, Ross DS, Weintraub BD 1997 Comparison of administration of recombinant human thyrotropin with withdrawal of thyroid hormone for radioactive iodine scanning in patients with thyroid carcinoma. N Engl J Med 337:888-896.(2). Meier CA, Braverman LE, Ebner SA, Veronikis I, Daniels GH, Ross DS, Deraska DJ, Davies TF, Valentine M, DeGroot LJ, Curran P, McEllin K, Reynolds J, Robbins J, Weintraub BD 1994 Diagnostic use of recombinant human thyrotropin in patients with thyroid carcinoma (phase I/II study). J Clin Endocrinol Metab 78:188-196.(3). FDA Website; Thyrogen Label and Approval History: http://www.accessdata.fda.gov/scripts/cder/drugsatfda/index.cfm?fuseaction=Search.Label_ApprovalHistory#apphist (4). Haugen BR, Pacini F, Reiners C, Schlumberger M, Ladenson PW, Sherman SI, Cooper DS, Graham KE, Braverman LE, Skarulis MC, Davies TF, DeGroot LJ, Mazzaferri EL, Daniels GH, Ross DS, Luster M, Samuels MH, Becker DV, Maxon HR, 3rd, Cavalieri RR, Spencer CA, McEllin K, Weintraub BD, Ridgway EC 1999 A comparison of recombinant human thyrotropin and thyroid hormone withdrawal for the detection of thyroid remnant or cancer. J Clin Endocrinol Metab 84:3877-3885.
Disclosure: KBA: Coinvestigator, Genzyme Corporation, Investigator, Celgene. Nothing to Disclose: SNN, EV, HW, MEO
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Sources of Research Support:
Thyroid Cancer Research Fund, University of Kentucky