[Indication and extent of cervical lymph node dissection in differentiated thyroid carcinoma]

Indication and extent of lymph node dissection in differentiated thyroid carcinoma are still subject to controversy. The overall favourable prognosis, low study numbers and the different biological features of papillary and follicular carcinoma lead to few evidence-based recommendations and a low level of evidence. The different therapeutic and operative strategies are illustrated on the principles of evidence-based medicine.

A literature search was carried out in Medline and EMBase using the keywords differentiated/papillary/follicular thyroid carcinoma, lymphadenectomy, lymph node dissection.

PTC: Eleven retrospective studies outline the effect of prophylactic vs. no lymph node dissection on tumour relapse rate and long-term survival. Six of these studies combine PTC and FTC. A minor evidence-based recommendation for prophylactic cervico-central lymph node dissection in PTC can be given (evidence level 3). Lymph node dissections involving the cervico-lateral compartment can be recommended in the case of clinically pathological findings at the lymph nodes (evidence level 3). A prophylactic mediastinal lymph node dissection is not indicated (evidence level 4), a therapeutic mediastinal LAD cannot be recommended because of higher morbidity and mortality (evidence level 3). FTC: 3 retrospective studies outline the effect of prophylactic lymph node dissection on tumour relapse rate and long-term survival. Based on these, a recommendation for prophylactic cervico-central systematic lymph node dissection can be given for invasive follicular carcinoma (evidence level 3). There is no indication for prophylactic cervico-lateral or mediastinal lymph node dissection (evidence level 3).

The following recommendations can be given in differentiated thyroid carcinoma: In the case of clinically pathological findings in cervical lymph nodes, a systematic lymph node dissection of the lateral and central compartment is indicated (evidence level 3). Prophylactic cervico-central lymph node dissection is recommended for PTC larger than 10 mm in diameter and invasive FTC, a cervico-lateral or mediastinal prophylactic lymph node dissection is not indicated (evidence level 3). In papillary microcarcinoma and minimally invasive follicular carcinoma, a prophylactic lymph node dissection is not indicated (evidence level 3).