The Use of 124-I-PET/CT Whole Body and Lesional Dosimetry in Differentiated Thyroid Cancer
Status:
Recruiting
Trial end date:
2029-02-01
Target enrollment:
Participant gender:
Summary
Study rationale
High risk patients with differentiated thyroid cancer (DTC) require therapy with 131 I under
thyroid stimulating hormone (TSH) stimulation. There are two methods of TSH stimulation
endogenous by thyroid hormone withdrawal (THW) leading to hypothyroidism and exogenous by
injection of human recombinant TSH (rhTSH Thyrogen). The appropriate 131-I activity utilized
for treatment is either based on empiric fixed dosage choice or individually determined
activity based on 131 I dosimetric calculations. Although dosimetry utilizing radioactive
iodine isotope 131 I enables calculation of maximum safe dose, it does not estimate the
tumoricidal activity necessary to destroy the metastatic lesions. The alternative radioactive
isotope of iodine -124 I, used for positron emission tomography (PET) imaging, might be used
for calculation not only the maximum safe131 I dose, but also to predict the absorbed dose in
the metastatic lesions.
Study objectives
The primary objective of this study is to compare the 124 I -PET/CT lesional and whole body
dosimetry in each individual patient with metastatic radioiodine (RAI)-avid thyroid cancer
under preparation with rhTSH and THW. The secondary objective is to evaluate the predicted by
PET/CT lesional uptake with the early response to therapy.
Study design
This is a phase 2 pilot prospective cohort study comparing the lesional and whole body
dosimetry within each patient undergoing exogenous (rhTSH) and endogenous (THW) TSH
stimulation and followed for 5 years.
Interventions
Each study participant will undergo rhTSH and THW-aided 124 I-PET/CT dosimetric evaluations
and will be subsequently treated with THW-aided RAI activity based on dosimetric calculations
enabling maximum safe dosage. The patients will be followed in 12+/-3 months intervals for 5
years.
Sample size and population
This pilot study will include 30 patients with high risk differentiated thyroid cancer
presenting with distant and/or loco-regional metastases.
Phase:
Phase 2
Details
Lead Sponsor:
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)