Persistent hypercalcitoninemia in patients with medullary thyroid cancer: a therapeutic approach based on selective venous sampling for calcitonin.

BACKGROUND Persistent or recurrent medullary thyroid carcinoma (MTC) can be cured by microdissection of residual metastatic lymph nodes in the neck. Selective venous sampling can be used for localization. The aim of this study is to prospectively analyze our results with a therapeutic approach based on venous sampling, in patients with hyperthyrocalcitoninemia after thyroidectomy for MTC. METHODS Selective venous sampling for determination of stimulated calcitonin was obtained in all patients after performing a complete laboratory and imaging workup. Patients with a gradient between the suprahepatic vein and the superior vena cava underwent unilateral or bilateral extensive lymph node dissection. We used the gradient between the right and left jugular veins to decide which side of the neck to operate. Calcitonin levels were obtained after surgery and a pentagastrin test was performed one year later if basal levels remained normal. RESULTS Mean age of the five women with a neck gradient in the selective venous sampling who underwent neck exploration was 45 years. In all patients metastatic lymph nodes were found at the site suggested by the study. Mean positive/resected lymph nodes were 5/20. Postoperative basal and stimulated levels of calcitonin became normal in two patients at one year of follow up. CONCLUSION Selective venous sampling is useful to localize recurrent MTC.