Value of the negative PET-FDG in the middle term follow-up of differentiated thyroid cancer in patients with negative 131 I-Na scan and elevated thyroglobulin serum levels.
OBJECTIVE
This study has aimed to analyze the evolution of patients diagnosed with differentiated thyroid carcinoma (DTC) with a negative (131)I-Na whole body scan (WBS), high levels of serum thyroglobulin (Tg) and negative (18F)fluorodeoxyglucose positron emission tomography (PET-FDG) study.


METHODS
Twenty-three patients diagnosed and treated for DTC were studied retrospectively. Patients were aged between 23 and 83 and had shown, between January 2001 and December 2002, negative WBS, Tg values in a range of suspected recurrence or metastasis (Tg>2 ng / mL with thyroid hormone withdrawal) and a negative PET-FDG study. The patients were monitored clinically, radiologically and analytically for a minimum period of 4 years. After this, a new evaluation was made of their state of disease with a control WBS, also observing the evolution of Tg. All WBS were performed with a 185 MBq diagnostic dose of (131)I-Na.


RESULTS
In 18/23 patients, Tg decreased and in 5 it increased. Four patients (17%) were free of active disease (negative WBS Tg<2 ng / mL). A total of 16 patients (70%) were free of disease according to the WBS but had elevated Tg. Three patients (13%) had disease and high levels of Tg, two of them with positive WBS and the third with (99m)Tc-MIBI scan and CT positive.


CONCLUSIONS
Most patients with a negative WBS, high Tg serum levels and negative FDG PET had good evolution, with descending Tg levels, normal levels even being reached in a significant percentage of them.
Unidad de Diagnóstico por la Imagen, Medicina Nuclear, Hospital Universitario Virgen del Rocío, Seville, Spain. victorpachon1@gmail.com
V M
VM
Pachón-Garrudo
J I
JI
Cuenca-Cuenca
J
J
Ruiz-Franco-Baux
I
I
Borrego-Dorado
J L
JL
Tirado-Hospital
E
E
Navarro-González
R
R
Vázquez-Albertino
D018263:Adenocarcinoma, Follicular / Q000097:blood / Q000000981:diagnostic imaging* / Q000556:secondary / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood; D014408:Biomarkers, Tumor / Q000097:blood*; D002291:Carcinoma, Papillary / Q000097:blood / Q000000981:diagnostic imaging* / Q000556:secondary / Q000601:surgery; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012974:Sodium Iodide; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood / Q000000981:diagnostic imaging* / Q000601:surgery; D013965:Thyroidectomy
D001323:Autoantibodies; D014408:Biomarkers, Tumor; D005462:Fluorine Radioisotopes; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; C006606:anti-thyroglobulin; D019788:Fluorodeoxyglucose F18; D013954:Thyroglobulin; D012974:Sodium Iodide