Is Prophylactic Lymphadenectomy Mandatory For Clinical N0 Medullary Thyroid Cancer? A Single Center Study

  • Introduction:
    Medullary thyroid carcinoma(MTC) accounts for 5-10% of all thyroid cancers and it’s known for its aggressive behaviour.

    We reviewed 102 patients diagnosed and operated at Lisbon Portuguese Institute of Oncology, Francisco Gentil between 1990-2015 with MTC.Pathological and analytical features, demographic characteristics, procedures and survival rate were analyzed.

    Of the total of 102 patients 85 were sporadic medullary thyroid cancer(SMTC) with a median follow-up time of 113 months. During this time, in SMTC, biochemical cure was obtained in 25 patients (29%) and 24 (28%) died. The survival rate at 5 years was 72%. 

    In the SMTC group, from the 44 (52%) patients without clinical lymph node involvement (cN0), 22 (50%) underwent prophylactic lymphadenectomy; 27% (6) of those patients were N positive after histopathological examination (pN1). No pN1 (6) died and 2 had biochemical cure. In those pN0 (16), 1 died and 11 had biochemical cure.

    The cN0 that underwent just total thyroidectomy 1(4%) died from the disease and 12 (54%) had biochemical cure.

    It was also observed that cN0 patients with preoperative calcitonin over 28000 pg/ml, 100% where pN1 after lymphadenectomy. The cN0 without lymphadenectomy with preoperative calcitonin over 28000 pg/ml had biochemical persistent disease.The calcitonin value was correlated with tumor size.

    We observed that 27% of the cN0 had already ganglionar metastasis. In 73% (16) of cN0 that underwent lymphadenectomy, this procedure was unnecessary. Based on the calcitonin pre-operatory we can determine in the cN0 the patients who should be systematically submitted to lymphadenectomy. A larger sample is needed to conclude prognostic value of prophylactic lymphadenectomy. 


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