Diagnostic value of recombinant human thyrotropin-stimulated ¹²³I whole-body scintigraphy in the follow-up of patients with differentiated thyroid cancer

Clin Nucl Med. 2012 Mar;37(3):229-34. doi: 10.1097/RLU.0b013e31823ea463.

Abstract

Purpose: Published data on recombinant human thyrotropin- (rhTSH-) stimulated iodine-123 (¹²³I) diagnostic whole-body scintigraphy (DxWBS) in differentiated thyroid cancer (DTC) surveillance after initial treatment are limited. We sought to evaluate this modality's diagnostic value in this setting.

Materials and methods: We retrospectively compared rhTSH-stimulated ¹²³I DxWBS results with DTC status concurrently determined by stimulated serum thyroglobulin (Tg) measurement, neck ultrasonography, and other imaging studies. Disease was considered present based on stimulated Tg level ≥1 μg/L without interfering Tg autoantibodies with or without positive imaging or biopsy-proven DTC. We also compared scan positivity and disease detection rates of rhTSH-stimulated DxWBS scans obtained with ¹²³I with those acquired with iodine-131 (¹³¹I) during the same period. The sample comprised 105 consecutive totally thyroidectomized patients undergoing rhTSH-aided DxWBS with I-123 (n = 67) or with ¹³¹I (n = 38) for diagnostic follow-up. rhTSH, 0.9 mg/d, was injected intramuscularly on 2 consecutive days. Oral diagnostic activities of 5 to 10 mCi (185-370 MBq) ¹²³I or 3 mCi (111 MBq) ¹³¹I were given on the third day. DxWBS was performed 24 hours (¹²³I) or 48 to 72 hours (¹³¹I) later.

Results: rhTSH-aided ¹²³I DxWBS scans showed 35.3% sensitivity, 98.0% specificity, 85.7% positive predictive value, and 81.6% negative predictive value. rhTSH-stimulated ¹²³I and ¹³¹I DxWBS did not differ in scan positivity (10.4% vs. 13.2%, P = 0.75) or disease detection rates (35.3% vs. 27.8%, P = 1.00).

Conclusions: In DTC, rhTSH-aided ¹²³I DxWBS achieves comparable results in diagnostic follow-up with those of rhTSH-aided ¹³¹I DxWBS. Future studies should address the preablation setting and scan activity and timing.

Publication types

  • Comparative Study

MeSH terms

  • Biomarkers, Tumor / blood
  • Biopsy
  • Chi-Square Distribution
  • Female
  • Follow-Up Studies
  • Humans
  • Iodine Radioisotopes*
  • Luminescent Measurements
  • Male
  • Middle Aged
  • Multimodal Imaging
  • Neoplasm Recurrence, Local / diagnostic imaging
  • Neoplasm, Residual / diagnostic imaging
  • Positron-Emission Tomography
  • Predictive Value of Tests
  • Recombinant Proteins
  • Retrospective Studies
  • Sensitivity and Specificity
  • Statistics, Nonparametric
  • Thyroglobulin / blood
  • Thyroid Neoplasms / blood
  • Thyroid Neoplasms / diagnostic imaging*
  • Thyroid Neoplasms / pathology
  • Thyroid Neoplasms / surgery
  • Thyroidectomy
  • Thyrotropin*
  • Tomography, X-Ray Computed
  • Whole Body Imaging*

Substances

  • Biomarkers, Tumor
  • Iodine Radioisotopes
  • Recombinant Proteins
  • Thyrotropin
  • Thyroglobulin