Identification of occult metastases of medullary thyroid carcinoma by pentagastrin-stimulated intravenous calcitonin sampling followed by targeted surgery.
BACKGROUND
High calcitonin (CT) serum levels suggest metastatic spread in medullary thyroid carcinoma (MTC) after thyroidectomy. In limited disease stages, however, morphological investigations including ultrasound, magnetic resonance imaging (MRI) and 18F-FDG positron emission tomography ([18F]FDG-PET) may often fail to identify exact tumour sites.


OBJECTIVE
The aim of the present study was to establish an improved strategy to identify small cervical tumours by combining pentagastrin stimulation with bilateral cervical intravenous CT sampling followed by high-resolution ultrasound.


METHODS
Six MTC patients were examined, of whom five patients already had bilateral neck dissection. Five patients had sporadic MTC, and one patient suffered from MEN2a.


RESULTS
Retrospective analysis of all patients revealed a highly sensitive positive correlation between an early calcitonin peak (20-40 s after pentagastrin injection) and site of cervical tumour affection. Postinterventional ultrasound examination of the affected regions of the neck revealed suspicious presence; in some cases small lymph nodes of less than 1 cm in size were then surgically excised. On histology, small tumours could be identified in four patients. Postsurgical examination revealed a clear decline of basal serum calcitonin levels in four patients (between -41% and -100%). In two patients CT normalized to baseline levels (< 10 pg/ml) and in another two patients CT rendered to near normal (14 and 17 pg/ml).


CONCLUSIONS
Pentagastrin stimulation-based intravenous catheter sampling may be beneficial in the diagnostic work-up of MTC after thyroidectomy. Our data show that an early calcitonin peak (20-40 s after administration of pentagastrin) helps to identify tumour-affected regions.
Schott
Matthias
M
Department of Endocrinology, Diabetes and Rheumatology, University Hospital Dusselsorf, Germany. schottmt@uni-duesseldorf.de
Willenberg
Holger S
HS
Sagert
Cornelia
C
Nguyen
Thi-Bang-Tam
TB
Schinner
Sven
S
Cohnen
Mathias
M
Cupisti
Kenko
K
Eisenberger
Claus F
CF
Knoefel
Wolfram T
WT
Scherbaum
Werner A
WA
D000328:Adult; D014408:Biomarkers, Tumor / Q000097:blood*; D002116:Calcitonin / Q000097:blood*; D018276:Carcinoma, Medullary / Q000556:secondary* / Q000601:surgery; D005260:Female; D006801:Humans; D049449:Luminescence; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D018813:Multiple Endocrine Neoplasia Type 2a / Q000556:secondary / Q000628:therapy; D018365:Neoplasm, Residual / Q000175:diagnosis* / Q000601:surgery; D010418:Pentagastrin; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000556:secondary* / Q000601:surgery; D013965:Thyroidectomy
D014408:Biomarkers, Tumor; D002116:Calcitonin; D010418:Pentagastrin