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Page 4 of 9 Shaha. J Cancer Metastasis Treat 2023;9:22 https://dx.doi.org/10.20517/2394-4722.2022.101

Table 2. Arguments for elective central neck dissection

• High incidence of central node metastasis
• Imaging studies may not be very helpful for the central compartment
• Future recurrence may be difficult to handle surgically
• Restaging of the thyroid cancer (stage migration)
• Consideration of radioactive iodine in some patients with multiple positive nodes
• Disease-free interval?
• Decreased recurrence rate
• Upstaging in patients above 55
• Safe procedure in experienced hands

Table 3. Arguments against elective central neck dissection

• Most of these are micrometastasis with no major impact on the outcome or prognosis
• Intraoperative evaluation is more important than elective nodal dissection
• Generous frozen section will help to select the patients who will be benefited from central compartment dissection
• High incidence of temporary and permanent hypoparathyroidism and nerve injury
• No benefit to survival
• Unless there are multiple positive nodes (more than 5) no need for radioactive iodine
• Even if patient recurs, surgical dissection is amenable with similar risks
• No clear evidence regarding unilateral or bilateral elective central node dissection
• Most thyroid surgery is not done by high-volume surgeons
• Conflicting data on survival and decreased recurrence
• The risk may outweigh the benefit
• “Primum non nocere” - first, do no harm

NON-SURGICAL MANAGEMENT OF NECK NODE METASTASIS
Decisions regarding the management of neck nodes in thyroid cancer are quite complex and, as mentioned
earlier, depend upon the extent of disease. It is not uncommon to find a suspicious but unproven small
lymph node in the neck. The metastatic disease may be quite small, and it may be very difficult to find.
Non-surgical approaches are available, including alcohol injection, as popularized at the Mayo Clinic . The
[17]
overall experience with alcohol injection is quite small, however, it has shown some remarkable results in
isolated low-risk metastatic thyroid cancers. It remains to be seen what the long-term follow-up of these
patients will evidence and whether it has any impact on subsequent surgical procedures. Other modalities
which are used anecdotally include radiofrequency ablation, microwave ablation, and laser ablation,
although these techniques are used more for benign thyroid pathologies, there appears to be some interest
in using them for primary malignant tumors of the thyroid or even metastatic disease, but the experience
remains limited around the world. A non-surgical approach is advised in small lymph nodes, which may be
difficult to find during surgery, and if not in close proximity to vital structures, could be monitored, as per
active surveillance. This requires detailed imaging studies with ultrasound and cross-sectional imaging with
continuous monitoring and repeat imaging in 9-12 months.

PROGNOSTIC INDICATORS IN THE NECK NODE METASTASIS FROM THYROID CANCER
The publication by Randolph et al. has described the risk of recurrence and prognostic factors in nodal
metastasis, starting from the lowest risk of recurrence to the highest risk of recurrence . One of the most
[18]
important prognostic factors is the number of lymph nodes removed and the number of positive nodes -
lymph node density or lymph node ratio. The metastatic number of lymph nodes of more than 10 is
considered to be at high risk for future recurrence. The ATA in the 2015 guidelines used 5 as a cut-off
between low- and intermediate-risk nodal metastasis . The size of the metastatic focus is also important
[19]
and again ATA used 2 mm as a cut-off. The size of the nodal metastasis is also important [Table 4]. Nodal
metastasis greater than 3 cm is considered to be prognostically concerning, as is extranodal extension.
Patients with major extranodal extension will have soft tissue extension into the surrounding tissues, which
has a high risk of future recurrence. Aggressive histology (e.g., tall cell, insular, hobnail, columnar, and