The treatment of thyroid cancer and associated involved lymph nodes needs to be carefully thought through and discussed as part of a multidisciplinary approach. It is a potentially lethal disease and must be respected as such. The treatment will often be multimodal including surgery, radio iodine, and TSH suppression with Thyroxine. Careful plans for the postoperative management and monitoring of the patient, including the measurement of thyroglobulin levels, intermittent scans, and clinical follow-up, will all be needed. There are several published guidelines regarding the treatment of thyroid cancer, including those published by the American thyroid Association (2009), the British Thyroid Association, and the British Association of Endocrine and Thyroid Surgeons (2007), together with a recently published evidence-based review of surgery for thyroid cancer published in the World Journal of Surgery (May 2007).

The obvious central strategy for the treatment of the disease is the complete removal of the primary tumor and, wherever possible, any extensions out with the thyroid gland, together with the removal of the relevant involved lymph nodes. Nevertheless, the execution of this relatively simple sounding strategy becomes somewhat more complicated as the individual variables for each patient are considered. Comorbidities in the patient, precise type of thyroid cancer, size of the primary involvement or otherwise of the lymph nodes, particular subtype of tumor together with personal and family history will all influence the final choices and options available to the patient. There is clear evidence that completeness of surgical resection is an important factor in securing a successful outcome, and recurrence within the neck remains the most common site of recurrence. Nevertheless, our understanding of the biology of thyroid cancer, particularly in relation to small primary tumors and small deposits within the lymph nodes, is incomplete. Overtreatment can result in considerable morbidity with no gain to the patient and undertreatment clearly may compromise the final outcome. As already mentioned in the section on “Diagnosis,” accurate preoperative staging of the disease by neck imaging is important. However, preoperative ultrasound does not identify all involved lymph nodes and is somewhat operator dependent. Lymph nodes in the neck are divided into anatomical compartments (see Fig. 1). The level 1 lymph node compartment is the submental and submandibular node compartments above the hyoid bone. Levels 2, 3, and 4 lymph nodes are aligned along the jugular veins on each side between the posterior border of the sterno cleido mastoid muscle and the anterior level 6 compartment. The level 5 nodes are in the posterior triangle lateral to the sterno mastoid muscle and the level 6 nodes are central, running from the hyoid bone down to the suprasternal notch. Superior mediastinal lymph nodes above the level of the innominate artery and in the upper mediastinum are referred to as level 7 nodes. Removal of the thyroid tumor in the neck and associated lymph nodes may well be an appropriate treatment even in the context of disseminated disease, since once the primary and loco regional nodes have been removed, metastases are more easily treated with radioactive iodine in the absence of other tissue avid for iodine. For goiters limited to the neck, ultrasound alone is the imaging modality of choice in planning treatment, but in retrosternal goiters or those where medullary thyroid cancer is thought to be present, CT or cross-sectional imaging of the mediastinum is advised. If the preoperative investigations have fallen short of a firm diagnosis of established thyroid cancer, then a diagnostic hemithyroidectomy is required on the affected side. Wherever possible, surgeons should try to remove all the thyroid tissues on the affected side at the time of a diagnostic lobectomy, so that further surgery is not required in that compartment. Revisional surgery to remove a remnant of thyroid tissue following an incomplete lobectomy is dangerous for the patient in terms of risks to the recurrent laryngeal nerve and parathyroid gland, as well as challenging and difficult for the surgeon. If a patient has a suspicious FNA biopsy and other features, which make it likely that they have a thyroid cancer in their history, or comorbidities which would make a second operation dangerous if the diagnostic lobectomy prove to be malignant, then a discussion can take place with the patient about the validity of proceeding immediately to a total thyroidectomy, even when the diagnosis falls short of confirmed thyroid cancer. This may be particularly relevant when the patient has a multinodular goiter, which in its own right, even if it is benign, might require total thyroidectomy. Because of multifocality in thyroid cancer of all types, if the primary tumor is >1 cm in size, then total thyroidectomy is the operation of choice. For a small subcentimeter low-risk thyroid cancer with no predisposing risks for further disease (e.g., radiation or family history) or evidence of disseminated disease (enlarged lymph nodes on ultrasound), a unilateral lobectomy may be sufficient. Nevertheless, the patient should be counselled that although metastasis and multifocality are unlikely with subcentimeter differentiated thyroid cancers, follow-up by using thyroglobulin measurements in patients with residual thyroid tissue and imaging the thyroid gland with radionuclide scans is more difficult when a normal lobe or part of a normal lobe has been left in situ.