Lymph node involvement in macroscopic medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a rare disease, with variable tendency to lymphatic spread. The aim of this retrospective study was to identify distinctive features of large MTC with and without nodal metastases. METHODS: Between 1993 and 2003, 28 consecutive patients underwent total thyroidectomy and neck node dissection for sporadic MTC larger than 10 mm in diameter. RESULTS: All tumours were confirmed to be malignant with a locally invasive pattern of growth. Lymph node metastases were present in 16 patients (N1) and absent in 12 (N0). There were no statistically significant differences between patients with N0 and N1 tumours concerning age (mean 52.1 versus 53.4 years), male:female ratio (0.7 versus 1.0), basal preoperative calcitonin concentration (mean 3238 versus 3076 pg/ml) and tumour size (23.3 versus 23.9 mm). There were differences in the incidence of tumour invasion (P < 0.001), vascular embolism (P = 0.011) and peritumoral thyroiditis (P = 0.039). Measurement of basal and stimulated calcitonin levels after surgery confirmed biochemical cure in all patients with N0 tumours and half of those with N1 disease (P = 0.006). CONCLUSION: There were no preoperative factors that predicted node status for MTC larger than 1 cm in this series. Total thyroidectomy and nodal dissection remains the optimal treatment.