Medullary thyroid cancer: prognostic factors for survival and recurrence, recommendations for the extent of lymph node dissection and for surgical therapy in recurrent disease.

BACKGROUND: We reviewed our experience with MTC (medullary thyroid cancer), focusing on recurrence and survival, recommendations for the extent of lymph node (LN) dissection and surgery for recurrent disease.

METHODS: Of 51 MTC patients treated between 1988 and 2008 at the University Hospitals Leuven, 38 previously untreated patients were analysed.

RESULTS: Overall and disease-specific (DSS) five-year survival rates were 75% and 82%. Variables univariately associated with DSS were age, pN, stage, vascular invasion, pre-operative recurrent laryngeal nerve function and last calcitonin level. Recurrence occurred in 10 patients (26%). For recurrence, age was no longer a prognostic factor and post-operative calcitonin, number of positive LN and of positive compartments proved to be prognostic factors. Of 21 clinical NO patients, 2 out of 6 (33%) undergoing a prophylactic central neck dissection (ND) based on per-operative palpatory suspicion proved pN+, and 2 out of 9 patients (22%) undergoing a prophylactic lateral ND were pN+. Five patients surgically treated for recurrence did not achieve long-term normalisation of calcitonin, but remained alive with locoregional control.

CONCLUSION: Overall survival and DSS rates are within the range reported in the literature. The results confirm that (1) total thyroidectomy and central compartment dissection is the treatment of choice in the cN0 patients, (2) additional ipsilateral lateral ND is needed for cN+ disease in the ipsilateral lateral compartment, and (3) in the clinically uninvolved contralateral lateral neck, per-operative inspection should serve as a basis for a decision about further ND. Locoregional control and prolonged survival is achieved in surgically treated locoregionally recurrent MTC.