99mTc-sestamibi radio-guided surgery of loco-regional 131Iodine-negative recurrent thyroid cancer.
OBJECTIVE
We report here our experience in a larger series of differentiated thyroid cancer (DTC) patients who had been treated by (99m)Tc-sestamibi radio-guided surgery (RGS) for (131)Iodine ((131)I)-negative loco-regional recurrent disease.


METHODS
Fifty-eight patients with loco-regional (131)I-negative recurrent disease from DTC were studied with (99m)Tc-sestamibi directed RGS using a hand-held 11-mm gamma probe as an intra-operative detector. Patients were selected for RGS on the basis of (a) progressive increase of serum thyroglobulin (Tg) levels after first treatment during follow-up, (b) negative high dose (100 mCi, 3.7 GBq) (131)I whole-body scan, and (c) positive pre-operative (99m)Tc-sestamibi scintigraphy for the presence of loco-regional recurrent disease. There were 41 papillary (1 "tall" cell variant), 13 follicular and 4 Hürthle cells tumours. In 14 patients thyroid cancer recurred in the thyroid bed while cervical lymph node metastases were found in 37 patients, and 7 patients had recurrent disease both in the thyroid bed and in cervical lymph nodes.


RESULTS
At bilateral neck exploration, 147 metastatic foci ranging from 4 mm to 51 mm in largest diameter (mean tumour diameter=17.3+/-9.5mm) were removed. Eighty-five of them (58%) had been pre-operatively identified at (99m)Tc-sestamibi scintigraphy. After RGS, serum Tg levels normalised in 43 of 58 patients (serum Tg<2 ng/ml--they were considered disease-free), serum Tg remained slightly increased in 12 patients without evidence of metastatic disease at scintigraphic and radiologic imaging (serum Tg<10 ng/mg--they were considered living with microscopic disease), while serum Tg significantly increased up to values>900 ng/ml in 3 patients who developed lung metastases. The mean lesion to background (99m)Tc-sestamibi uptake ratios decreased in all 58 patients (p<0.0001). Post-surgical follow-up ranged 6-72 months (mean+/-SD=29.6+/-13.5 months). The operating surgeon assessed RGS as very useful in 14 patients in whom metastatic foci were embedded in fibrotic tissues or located behind blood vessels, useful in 22 patients, moderately useful 17 patients and not useful in 5 patients.


CONCLUSIONS
Our data suggest that a (99m)Tc-sestamibi intra-operative gamma probe can be used to identify and guide resection of recurrent loco-regional tumour in DTC patients with (131)I-negative loco-regional metastatic foci.
Rubello
D
D
Nuclear Medicine and PET Service, S. Maria della Misericordia Rovigo Hospital, Viale Tre Martiri 140, I-45100 Rovigo, Italy. domenico.rubello@libero.it
Salvatori
M
M
Casara
D
D
Piotto
A
A
Toniato
A
A
Gross
M D
MD
Al-Nahhas
A
A
Muzzio
P C
PC
Pelizzo
M R
MR
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000601:surgery; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D017256:Technetium Tc 99m Sestamibi; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000601:surgery*; D013965:Thyroidectomy / Q000379:methods*; D016896:Treatment Outcome
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi