Selective venous sampling catheterisation for localisation of persisting medullary thyroid carcinoma.

Selective venous sampling catheterisation was performed in 19 patients with medullary thyroid carcinoma without known distant metastases for persistent hypercalcitoninaemia after surgery. Calcitonin (CT) gradients were found in the neck and/or the mediastinum in 18 patients and in five patients at distant sites also. After venous catheterisation, 13 patients were subjected to repeat surgery. Neck and/or mediastinal tumour foci were found in 12 patients at the sites of the CT gradients. Of these, nine patients had only cervicomediastinal CT gradients: after reoperation, the serum CT level normalised in one, significantly decreased in five, and did not change in three, and no neck relapse occurred after a mean follow-up of 5.3 years. Distant metastases emerged clinically in all five patients with distant gradients and in only one of the 14 patients with no distant gradient. In conclusion, selective venous catheterisation is the most sensitive tool for the localisation of residual disease and for the early detection of distant metastases. However, in patients with only local disease, biochemical cure is rarely obtained after reoperation.