<s>[INST] context: . A total thyroidectomy with bilateral neck dissection is the gold standard for treating medullary thyroid cancer, and is the most definitive means of achieving a cure in patients without distant metastases or extensive nodal involvement. Due to the extreme level of difficulty in successfully performing the neck dissection without extensive morbidity, it is very impoant for patients to seek care under an experienced surgeon at a Center of Excellence who operates on MTC patients at least several times a year. Risks of surgery include loss of vocal control, irreparable nerve damage, death or the need for second operation to clean out residual diseased lymph nodes left behind if the sentinel node biopsy was positive for cancerous spread. Extensive surgery can be effective when the condition is detected early, but a risk for recurrence remains, paicularly in patients with multiple positive lymph nodes or extracapsular invasion. About half of patients have metastasis to regional lymph nodes at the time of diagnosis. [/INST] question: Treatment of Medullary Carcinoma thyroid | options: A: Surgery and radiotherapy B: Radiotherapy and chemotherapy C: Surgery only D: Radioiodine ablation | answer: C </s>