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P>BackgroundPositron emission tomography (PET) using fluorodeoxyglucose (FDG) has proven to be more sensitive and accurate than other imaging modalities for the detection of distant metastases in patients with melanoma. Sentinel lymph node (SLN) status is the most important prognostic factor in melanoma patients with no evidence of distant metastasis.ObjectivesTo assess the rate of distant metastases in patients with a positive SLN biopsy (SLNB).MethodsForty-six consecutive patients with a positive SLNB underwent PET or PET-computed tomography within 6 weeks of the SLNB procedure. The patients did not present any clinical sign of nodal involvement or of distant metastasis. PET findings were classified as positive, negative or nonconclusive.ResultsNo patient had a positive PET scan for distant metastasis. Six patients (13%) had a nonconclusive PET scan; none of them presented distant metastasis within 12 months. Forty patients (87%) had a negative PET scan; among them five (12%) presented with distant metastasis within 12 months.ConclusionsFluorodeoxyglucose positron emission tomography failed to detect distant metastases at initial staging in patients with a positive SLNB, even in patients who presented with distant metastases within 12 months after the FDG PET scan. These results could be explained by the low prevalence of macroscopic metastatic disease at this stage and by the important delay between the onset of the spread of microscopic metastatic disease and the identification by PET scan of macroscopic metastatic disease.

O câncer de tireóide é responsável por cerca de 1% dos novos casos de doença maligna diagnosticados. A maioria destes tumores são carcinomas papilares e foliculares, também denominados de carcinomas diferenciados de tireóide (CDT). Estes carcinomas têm uma taxa de cura de aproximadamente 80%, enquanto 20% apresentarão recorrência local e 5 a 10% desenvolverão metástases à distância. Porém, alguns pacientes apresentam uma doença mais agressiva. A identificação de tais pacientes tem grande impacto no manejo clínico do CDT. Várias classificações de estádio clínico e fatores prognósticos são apresentados, bem como os principais exames para seguimento dos pacientes com CDT. Thyroid carcinoma accounts for roughly 1% of all new malignant diseases. Of these, at least 94% are differentiated thyroid carcinoma (DTC), either papillary thyroid carcinoma or follicular thyroid carcinoma. Patients with DTC are usually considered as having a good prognosis, 80% of patients are cured, 20% will develop loco-regional recurrence and 5- 10% distant metastasis. However, the disease may have an aggressive course in some patients. The identification of these patients has a major impact in the clinical management of DTC. Several prognostic factors and classification will be addressed, as well the most useful tests for patient’s follow-up.

P>Background Positron emission tomography (PET) using fluorodeoxyglucose (FDG) has proven to be more sensitive and accurate than other imaging modalities for the detection of distant metastases in patients with melanoma. Sentinel lymph node (SLN) status is the most important prognostic factor in melanoma patients with no evidence of distant metastasis. Objectives To assess the rate of distant metastases in patients with a positive SLN biopsy (SLNB). Methods Forty-six consecutive patients with a positive SLNB underwent PET or PET-computed tomography within 6 weeks of the SLNB procedure. The patients did not present any clinical sign of nodal involvement or of distant metastasis. PET findings were classified as positive, negative or nonconclusive. Results No patient had a positive PET scan for distant metastasis. Six patients (13%) had a nonconclusive PET scan; none of them presented distant metastasis within 12 months. Forty patients (87%) had a negative PET scan; among them five (12%) presented with distant metastasis within 12 months. Conclusions Fluorodeoxyglucose positron emission tomography failed to detect distant metastases at initial staging in patients with a positive SLNB, even in patients who presented with distant metastases within 12 months after the FDG PET scan. These results could be explained by the low prevalence of macroscopic metastatic disease at this stage and by the important delay between the onset of the spread of microscopic metastatic disease and the identification by PET scan of macroscopic metastatic disease.

P>Background Positron emission tomography (PET) using fluorodeoxyglucose (FDG) has proven to be more sensitive and accurate than other imaging modalities for the detection of distant metastases in patients with melanoma. Sentinel lymph node (SLN) status is the most important prognostic factor in melanoma patients with no evidence of distant metastasis. Objectives To assess the rate of distant metastases in patients with a positive SLN biopsy (SLNB). Methods Forty-six consecutive patients with a positive SLNB underwent PET or PET-computed tomography within 6 weeks of the SLNB procedure. The patients did not present any clinical sign of nodal involvement or of distant metastasis. PET findings were classified as positive, negative or nonconclusive. Results No patient had a positive PET scan for distant metastasis. Six patients (13%) had a nonconclusive PET scan; none of them presented distant metastasis within 12 months. Forty patients (87%) had a negative PET scan; among them five (12%) presented with distant metastasis within 12 months. Conclusions Fluorodeoxyglucose positron emission tomography failed to detect distant metastases at initial staging in patients with a positive SLNB, even in patients who presented with distant metastases within 12 months after the FDG PET scan. These results could be explained by the low prevalence of macroscopic metastatic disease at this stage and by the important delay between the onset of the spread of microscopic metastatic disease and the identification by PET scan of macroscopic metastatic disease.