Treatment for differentiated thyroid cancer (papillary, follicular) usually begins with a a total or nearly total thyroidectomy ( removal of both lobes and isthmus of the thyroid gland).
Prior to surgery, the American Thyroid Association (ATA) and European Thyroid Association (ETA) Guidelines for the management of thyroid cancer advise preoperative neck ultrasonography, both in adults and children, to carefully inspect the lymph node compartments in the lateral and central neck for metastases.
In addition, at surgery the surgeon normally inspects the neck for enlarged lymph nodes, but ultrasonography is more likely to identify small malignant lymph nodes than is feeling the neck during surgery.
The surgeon may alter the extent of the initial surgery, depending on the size of the thyroid tumor and whether or not there is evidence of lymph node metastases and/or tumor invading the thin capsule of the thyroid into surrounding neck tissues. Tumor that is outside the confines of the thyroid gland, and that is invading the soft tissues of the neck, can usually be removed without injury to the neck muscles or recurrent laryngeal nerve needed by the vocal cords.
Abnormal-appearing or biopsy-proven metastatic lymph nodes are excised during surgery. In the past, only selected lymph nodes thought to be involved with tumor were removed, a procedure called selective lymph node dissection. However, now both the ATA and ETA guidelines suggest total removal of entire groups of lymph nodes within one or another neck compartment only if at least one malignant lymph node is found.
Some surgeons prophylactically remove all the lymph nodes in the central neck when the patient has a very aggressive tumor, whether or not any are known to be malignant at the time of surgery. In most cases, however, this is not done in children with differentiated thyroid cancer without a clear diagnosis of metastatic tumor in at least one lymph node. In adults, the ATA but not the ETA advise prophylactic lymph node dissection of the central neck lymph node compartments.