Follow-up of low-risk differentiated thyroid cancer patients who underwent radioiodine ablation of postsurgical thyroid remnants after either recombinant human thyrotropin or thyroid hormone withdrawal.
BACKGROUND
We previously demonstrated comparable thyroid remnant ablation rates in postoperative low-risk thyroid cancer patients prepared for administration of 3.7GBq (131)I (100 mCi) after recombinant human (rh) TSH during T(4) (L-T4) therapy vs. withholding L-T4 (euthyroid vs. hypothyroid groups). We now compared the outcomes of these patients 3.7 yr later.


METHODS
Fifty-one of the 63 original patients (28 euthyroid, 23 hypothyroid) participated. Forty-eight received rhTSH and serum thyroglobulin (Tg) sampling. A (131)I whole-body scan was performed in 43 patients, and successful ablation was defined by criteria from the previous study. Based on the criterion of uptake less than 0.1% in thyroid bed, 100% (43 of 43) remained ablated. When no visible uptake instead was used, five patients (four euthyroid, one hypothyroid) had minimal visible activity. When the TSH-stimulated Tg criterion was used, only two of 45 (one euthyroid, one hypothyroid) had a stimulated Tg level greater than 2 ng/ml.


RESULTS
No patient in either group died, and no patient declared disease free had sustained tumor recurrence. Nine (four euthyroid, five hypothyroid) had received additional (131)I between the original and current studies due to detectable Tg or imaging evidence of disease; with follow-up, all now had a negative rhTSH-stimulated whole-body scan and seven (three euthyroid, four hypothyroid) had a stimulated serum Tg less than 2 ng/ml.


CONCLUSIONS
In conclusion, after a median 3.7 yr, low-risk thyroid cancer patients prepared for postoperative remnant ablation either with rhTSH or after L-T4 withdrawal were confirmed to have had their thyroid remnants ablated and to have comparable rates of tumor recurrence and persistence.
Elisei
R
R
Department of Endocrinology, University of Pisa, 56124 Pisa, Italy. relisei@endoc.med.unipi.it
Schlumberger
M
M
Driedger
A
A
Reiners
C
C
Kloos
R T
RT
Sherman
S I
SI
Haugen
B
B
Corone
C
C
Molinaro
E
E
Grasso
L
L
Leboulleux
S
S
Rachinsky
I
I
Luster
M
M
Lassmann
M
M
Busaidy
N L
NL
Wahl
R L
RL
Pacini
F
F
Cho
S Y
SY
Magner
J
J
Pinchera
A
A
Ladenson
P W
PW
D018263:Adenocarcinoma, Follicular / Q000188:drug therapy / Q000532:radiotherapy / Q000601:surgery; D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000188:drug therapy / Q000532:radiotherapy / Q000601:surgery; D003131:Combined Modality Therapy; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000627:therapeutic use; D013954:Thyroglobulin / Q000097:blood; D013963:Thyroid Hormones / Q000008:administration & dosage*; D013964:Thyroid Neoplasms / Q000188:drug therapy / Q000532:radiotherapy* / Q000601:surgery; D013965:Thyroidectomy; D013972:Thyrotropin / Q000627:therapeutic use*; D016896:Treatment Outcome
D007457:Iodine Radioisotopes; D011994:Recombinant Proteins; D013963:Thyroid Hormones; D013972:Thyrotropin; D013954:Thyroglobulin