Reoperation in metastasizing medullary thyroid carcinoma: is a tumor stage-oriented approach justified?

Lymph node metastases (LNM) are very often found in medullary thyroid carcinoma. After primary therapy, elevated levels of calcitonin are measurable in many patients. Because of the low sensitivity and specificity of diagnostic tools to detect micrometastases, the question remains whether an extended lymphadenectomy improves the chance of cure and whether this approach should be tumor stage oriented.

We analyzed the results of 36 patients with medullary thyroid carcinoma consecutively reoperated from 1988 to 1996, performing microdissection of all four locoregional lymph node compartments.

Pathologic tumor stage (pT) category was classified as pT1, n = 3; pT2 n = 22; pT3, n = 6; and pT4, n = 5. LNM were found in 34 patients (94%). The cervicocentral compartment contained LNM in 85%, the cervicolateral compartments in 41% to 54%, and the upper mediastinum in 36%. Patients with different pT category did not differ in the rate of LNM. Ipsilateral cervicolateral LNM were found in 50% to 71% and contralateral cervicolateral LNM in 14% to 40%. Nine (35%) of 26 patients without distant metastases were biochemically cured. In 10 patients (38%) calcitonin level decreased more than 50%.

LNM were almost always (94%) found in patients who have elevated calcitonin levels after primary therapy. In patients without distant metastases, four-compartment lymphadenectomy gives a chance of cure in 35%. A tumor stage-oriented approach does not seem to be justified.