¹³¹I treatment of toxic nodular goiter under combined thyrostatic-thyromimetic medication is at low risk of late hypothyroidism.
OBJECTIVE
Treatment of toxic nodular goiter with ¹³¹I is a first-line therapy for hyperthyroidism. To avoid a thyrotoxic storm, ¹³¹I is usually administered after pretreatment with antithyroid drugs, with thyroid-stimulating hormone (TSH) increase and functional recruitment of inhibited normal tissue. Therefore, both autonomous nodule(s) and normal tissue are irradiated. This may be a reason for late hypothyroidism occurring in 15-25% of patients. This study aimed at assessing different pretreatment modalities with combined methymazole and triiodothyronine, achieving euthyroidism with suppressed TSH.


METHODS
After diagnosis of autonomously functioning toxic nodule, patients were subjected to thyrostatic medication. Two months later, TSH was checked; if >0.5 mU/L triiodothyronine treatment was associated. After 2 more months, if the TSH level was suppressed, patients received ¹³¹I-therapy. A total of 149 patients were consecutively enrolled, 41 of whom with uninodular and 108 with multinodular goiter. They were evaluated at diagnosis, pretreatment, 3 and 6 months after therapy and at late follow-up (6.8+/-4.2 years; range: 1-22 years).


RESULTS
Administered activity was calculated according to ¹³¹I uptake and gland weight. Methymazole was discontinued 6 days before treatment and T3 was maintained until administration of ¹³¹I-therapy. Euthyroidism was achieved in 88% of patients. At late follow-up, subclinical hypothyroidism was observed in 10 patients (6.7%) and overt hypothyroidism in 5 patients (3.3%). No pathological consequences or side effects of ¹³¹I-therapy were found during the 6.8+/-4.2 year follow-up period.


CONCLUSIONS
Treatment of toxic nodular goiter with ¹³¹I-therapy, under combined thyrostatic-thyromimetic treatment is a simple, safe, well-tolerated, and effective procedure.
Paghera
B
B
Unit of Nuclear Medicine, Civilian Hospitals of Brescia, Brescia, Italy.
Panarotto
M B
MB
Maira
G
G
Magri
G C
GC
Bertagna
F
F
Bosio
G
G
Rossini
P
P
De Agostini
A
A
Savelli
G
G
Lucchini
S
S
Giubbini
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D013956:Antithyroid Agents / Q000627:therapeutic use; D003131:Combined Modality Therapy; D005260:Female; D006044:Goiter, Nodular / Q000188:drug therapy* / Q000532:radiotherapy*; D006801:Humans; D007037:Hypothyroidism / Q000517:prevention & control; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008713:Methimazole / Q000627:therapeutic use; D008875:Middle Aged; D013971:Thyrotoxicosis / Q000188:drug therapy* / Q000532:radiotherapy*; D013997:Time Factors; D014284:Triiodothyronine / Q000627:therapeutic use
D013956:Antithyroid Agents; D007457:Iodine Radioisotopes; D014284:Triiodothyronine; D008713:Methimazole