Key Points
- Thyroid cancer is the most common endocrine malignancy. In 2014 it is estimated that 96% of all new endocrine organ cancers will originate from the thyroid gland, resulting in approximately 63,000 new cases and taking the lives of 1890 patients.
- Gross lymph node metastases can be present in approximately 35% of patients with differentiated thyroid cancer (DTC).
- Although lymph node metastases are common in DTC, death is not, and the lack of a clear prognostic indication has led to controversy in the management of cervical lymph nodes.
- What may be more significant from a prognostic standpoint are lymph node metastases that are larger than 3 cm, exhibit extranodal extension, or metastasis present in more than five lymph nodes.
- Identification of recurrent/persistent disease requires a team decision-making process that includes the patient and physicians as to what, if any, intervention should be performed to best control the disease while minimizing morbidity.
Diagnosis
Table 1. Variables to Consider When Deciding How Best to Manage a Differentiated Thyroid Cancer Patient with Recurrent/Persistent Nodal Disease
| Variables | Consider active surveillance | Consider surgery |
|---|---|---|
| Key considerations | ||
| Absolute size of lymph nodes (any dimension)a |
|
|
| Rate of lymph node growth on serial imaging | Minimal/slow (<3–5 mm/year) | Progressive (>3–5 mm/year) |
| Vocal cord paralysis contralateral to the paratracheal nodal basin where the positive lymph node is located (next to only working RLN) | Strongly consider observation if node is stable | Consider surgery if node is increasing in size and expertise for reoperative surgery available |
| Known systemic metastases | Progressive distant disease outpacing nodal metastasis | Stable distant metastasis, but nodal disease threatens vital structures |
| Comorbidities for surgery | Yes | No |
| Invasion into/proximity to critical anatomic structures | No | Yes |
| Good long-term prognosis | No | Yes |
| Patient wishes to undergo surgery | No | Yes |
| Disease likely to be identified intraoperatively | No | Yes |
| Biological considerations | ||
| RAI-avidb | Yes | No (unless other criteria for surgery met) |
| FDG-PET-avid | No | Yes |
| Aggressive histology | No | Yes |
| Extrathyroidal extension of primary tumor | No | Yes |
| More advanced initial T stage (>4 cm) and more advanced nodal disease | No | Yes |
| Extranodal extension (features of nodes at initial surgery) | No | Yes |
| Molecular prognosticator for aggressive biology (see full text of article) | No | Yes |
| Surgical technical considerations | ||
| First recurrence in that compartment? | No | Yes |
| Recurrent or persistent disease in previously formally dissected compartment or multiple dissections in same compartmentc | Stable disease | Limited/focused dissection if progressive disease and threatening important structures |
| a Most authors agree that nodes <1 cm can usually be observed. However, depending on the unique situation of each patient, it may be reasonable to avoid surgery on nodes as large as 1.5–2 cm in carefully selected patients. b Active surveillance or RAI therapy are both reasonable options if the lymph node metastasis is RAI-avid. c Initial intervention was a formal attempt at central or lateral neck dissection and not just a node plucking or limited retrieval of nodes. | ||
