7. Node dissection for thyroid cancer - AAES guidelines
Lymph node metastases from thyroid cancer, especially papillary thyroid cancer cancer, can occur in up to 75% of cases without any clinical abnormality being present in the neck (subclinical involvement). All patients with thyroid cancer should have evaluation of the nodal status by ultrasound or CT scan. If lymph nodes are involved in with the central compartment (levels 6 and 7 close to the thyroid) or the lateral compartment ( levels 2,3,4,and 5 beyond the central compartment) they should be removed as a "therapeutic" node dissection. The issue of "prophylactic" node dissection of the central compartment where no node involvement has been demonstrated is controversial. The rational is that removal of microscopic disease before clinical presentation avoids the potential of added morbidity of re-operation, allows accurate disease staging, and reduces recurrence. The argument against routine prophylactic central node dissection is that itincreases the risk of complications with reported incidences of permanent hypoparathyroidism in some US centres of 18% as well as an increased risk of permanent recurrent laryngeal nerve palsy of over 4%.
Comment: Whilst routine prophylactic central node dissection has fallen out of favour in many parts of the USA it remains the preferred approach in major Australian centres. As always it is a matter of experience and technique with the reported complication incidence in Australian series of under 1%, ie no more than with total thyroidectomy alone. As such the advances of removing lymph node metastases before clinical disease becomes apparent are both significant and meaningful.