A comparison of 1850 (50 mCi) and 3700 MBq (100 mCi) 131-iodine administered doses for recombinant thyrotropin-stimulated postoperative thyroid remnant ablation in differentiated thyroid cancer.
OBJECTIVE
Recently, a multicenter study in differentiated thyroid cancer (DTC) patients showed that 3700 MBq 131-iodine ((131)I) after recombinant human TSH (rhTSH) had a successful thyroid ablation rate similar to that obtained after thyroid hormone withdrawal. We investigated whether 1850 MBq (131)I had a similar successful rate to 3700 MBq in patients prepared with rhTSH.


METHODS
A total of 72 patients with DTC were randomly assigned to receive 1850 (group A, n = 36) or 3700 MBq (group B, n = 36) (131)I after rhTSH. One injection of 0.9 mg rhTSH was administered for 2 consecutive days; (131)I therapy was delivered 24 h after the last injection, followed by a posttherapy whole-body scan. Successful ablation was assessed 6-8 months later.


RESULTS
Successful ablation (no visible uptake in the diagnostic whole-body scan after rhTSH stimulation) was achieved in 88.9% of group A and B patients. Basal and rhTSH-stimulated serum thyroglobulin was undetectable (<1 ng/ml) in 78.9% of group A and 66.6% of group B patients (P = 0.46). Similar rates of ablation were obtained in both groups also in patients with node metastases.


CONCLUSIONS
Therapeutic (131)I activities of 1850 MBq are equally effective as 3700 MBq for thyroid ablation in DTC patients prepared with rhTSH, even in the presence of node metastases.
Pilli
Tania
T
Department of Internal Medicine, Endocrinology and Metabolism and Biochemistry, Section of Nuclear Medicine, University of Siena, 53100 Sienna, Italy.
Brianzoni
Ernesto
E
Capoccetti
Francesca
F
Castagna
Maria Grazia
MG
Fattori
Sara
S
Poggiu
Angela
A
Rossi
Gloria
G
Ferretti
Francesca
F
Guarino
Elisa
E
Burroni
Luca
L
Vattimo
Angelo
A
Cipri
Claudia
C
Pacini
Furio
F
D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D017024:Chemotherapy, Adjuvant; D018450:Disease Progression; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D018365:Neoplasm, Residual; D011874:Radiometry; D011879:Radiotherapy Dosage; D011994:Recombinant Proteins / Q000627:therapeutic use; D016879:Salvage Therapy; D013964:Thyroid Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D013972:Thyrotropin / Q000627:therapeutic use*
D007457:Iodine Radioisotopes; D011994:Recombinant Proteins; D013972:Thyrotropin