(131)I treatment is highly effective in younger patients with (131)I uptake and with small metastases. They should be treated until the disappearance of any uptake or until a cumulative activity of 22 GBq has been administered. In the other patients, other treatment modalities should be used when tumor progression has been documented.

We highlight an excellent survival rate and suggest risk classifications of persistent and recurrent disease based on the numbers of LN metastases and ECE-LN, LN metastases location, tumor size, and thyroglobulin level.

Context: Neck ultrasonography (US) has become a keystone in the follow-up of patients with differentiated thyroid cancer.Objective: The aim of this study was to determine specificity and sensitivity of ultrasound criteria of malignancy for cervical lymph nodes (LNs) in patients with differentiated thyroid cancer. Design:We prospectively studied 19 patients referred to the Institut Gustave Roussy for neck LN dissection. All patients underwent a neck US within 4 d prior to surgery. Only LNs that were unequivocally matched between US and pathology were taken into account for the analysis. Results:One hundred three LNs were detected on US, 578 LNs were surgically removed, and 56 LNs were analyzed (28 benign and 28 malignant). Sensitivity and specificity were 68 and 75% for the long axis (Ն1 cm), 61 and 96% for the short axis (Ͼ5 mm), 46 and 64% for the round shape (long to short axis ratio Ͻ 2), 100 and 29% for the loss of fatty hyperechoic hilum, 39 and 18% for hypoechogenicity, 11 and 100% for cystic appearance, 46 and 100% for hyperechoic punctuations, and 86 and 82% for peripheral vascularization. Conclusion:Cystic appearance, hyperechoic punctuations, loss of hilum, and peripheral vascularization can be considered as major ultrasound criteria of LN malignancy. LNs with cystic appearance or hyperechoic punctuations are highly suspicious of malignancy. LNs with a hyperechoic hilum should be considered as benign. Peripheral vascularization has the best sensitivity-specificity compromise. Round shape, hypoechogenicity, and the loss of hilum taken as single criteria are not specific enough to suspect malignancy. N ECK ULTRASONOGRAPHY (US) has replaced radioactive iodine in the follow-up of patients with differentiated thyroid cancer (DTC) (1, 2). Sensitivity of US for the diagnosis of neck recurrence ranges from 70 to 100% (3-5). Metastatic lymph nodes (LNs) tend to be large, round, hypoechoic, and hypervascularized with a loss of hilar architecture (6 -13). In DTC, metastatic LNs may also demonstrate specific features such as hyperechoic punctuations or microcalcifications and cystic appearance (14 -16). The specificity of these US criteria in DTC is, however, not well known and difficult to assess on follow-up only because of the indolent nature of DTC. Specificity of US criteria based on pathology are, in fact, not available in DTC. Confirmation of malignancy of suspicious LN found on US is usually recommended and consists in a fine-needle aspiration biopsy (FNAB) for cytology and thyroglobulin determination in the aspirate fluid (17). There is a need for specific criteria of malignancy; otherwise, a majority of DTC patients will be submitted to FNAB, a stressful examination with potential morbidity.We therefore assessed both sensitivity and specificity of US criteria based on pathology in patients planned to neck LN dissection for DTC neck recurrence. Patients and Methods PatientsPatients referred to the Institut Gustave Roussy from February 2004 to January 2005 for surgical treatment of a neck recurrence of DTC...

The most efficient imaging work-up for depicting MTC tumor sites would consist of a neck US, chest CT, liver MRI, bone scintigraphy, and axial skeleton MRI. FDG PET scan appeared to be less sensitive and of low prognostic value.

Precise LN staging by prophylactic neck dissection for tumors initially staged T1N0 modified the indication for radioiodine ablation for 30% of patients.