[Evaluation of efficacy and clinical impact of 18F-FDG-PET in the diagnosis of recurrent medullary thyroid cancer with increased calcitonin and negative imaging test].
OBJECTIVE
To evaluate the efficacy and clinical impact of the FDG-PET in the diagnosis of suspicion of recurrence of medullary thyroid cancer (MTC) in patients with elevated serum calcitonin and negative imaging test.


METHODS
We performed a retrospective study of 31 consecutive cases from february 2001 to october 2007 of 17 women and 14 men, mean age 56.2 years (range: 26-88), with anatomical-pathology diagnosis of medullary thyroid cancer and suspicion of recurrence due to abnormal elevation of calcitonin and negative imaging tests. All of the patients underwent whole body FDG-PET scan with a dedicated PET or PET-CT 60 minutes after intravenous injection of 333-434 MBq of (18)F-FDG. Results were confirmed by pathology study in 45.2% of the patients and by clinical follow-up with a mean of 4 years (range: 16 m-8 years)


RESULTS
Sensitivity was 88%, specificity 84.6%, positive predictive value 88%, negative predictive value 84.6% and diagnostic accuracy 87%. The results of the FDG PET modified the therapeutic strategy in 14 cases (45.2%). A comparison was made of the mean values of calcitonin using the Student's "t" test between positive PET studies for the disease and negative ones. No significant differences were found (P=.3).


CONCLUSIONS
In patients with MTC and suspected recurrence with elevated calcitonin and negative imaging test, the FDG is the best test for the diagnosis of occult recurrence in MTC with elevated calcitonin and negative imaging techniques with elevated clinical impact. It facilitates the therapeutic management of the patients with MTC recurrence, and should be included in the diagnosis algorithm in these patients.
Unidad Diagnóstica de Gestión de Medicina Nuclear, Hospital Universitario Virgen del Rocío, Sevilla, Spain. mp.gomez.sspa@juntadeandalucia.es
P
P
Gómez-Camarero
A
A
Ortiz-de Tena
I
I
Borrego-Dorado
R J
RJ
Vázquez-Albertino
E
E
Navarro-González
J V
JV
Ruiz-Franco-Baux
J I
JI
Cuenca-Cuenca
D014408:Biomarkers, Tumor / Q000097:blood*; D001859:Bone Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000556:secondary; D002116:Calcitonin / Q000097:blood*; D018276:Carcinoma, Medullary / Q000097:blood / Q000000981:diagnostic imaging / Q000556:secondary* / Q000601:surgery; D018450:Disease Progression; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008113:Liver Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000556:secondary; D008175:Lung Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000556:secondary; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D018813:Multiple Endocrine Neoplasia Type 2a / Q000000981:diagnostic imaging; D018814:Multiple Endocrine Neoplasia Type 2b / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000097:blood / Q000000981:diagnostic imaging* / Q000601:surgery; D013965:Thyroidectomy
D014408:Biomarkers, Tumor; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D002116:Calcitonin