European Multicenter Study on Role of Lymph Node Dissection in Surgical Management of Adrenal Cortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare malignancy with an estimated annual incidence of only 0.5 to 2.0 per million population and a high rate of mortality: Stage I, II and III 5 years-survival is respectively 84%, 63% and 24%, while medium survival is less than 12 months for metastatic disease. Stage of the disease, age at diagnosis, tumour grading and complete surgical resection are the main prognostic factors. Surgical treatment is the only effective therapeutic strategy for ACC and recent guidelines recommend loco-regional lymph node dissection as a fundamental surgical element in order to guarantee complete resection. However, adrenal lymphatic drainage can be variable. The main collecting lymph nodes representing the first tiers in the lymphatic drainage are the peri-adrenal nodes and the renal ilum nodes. In addition, the posterior lymphatic drainage flows to lymph nodes located posterior to the IVC, and on the right edge of the aorta for the right adrenal gland, or on its right left edge for the left gland, stretching from the celiac region near the diaphragmatic crus to the renal vessels.

The anterior lymphatic drainage flows downward to the lumboaortic nodes and ends in the interaortocaval space, on the right edge of the aorta for the right adrenal gland, and on its right left edge for the left gland and mainly around the renal hilum. Collecting nodes can be located below the renal pedicle, sometimes extending as far as the origin of the iliac vessel. Most authors concur in describing a lymphatic drainage that passes through the diaphragm directly into the posterior mediastinal nodes. A majority of lymphatic channels run medially to the thoracic duct, often without the involvement of any lymph nodes. Furthermore, it is impossible to predict which pathway would be involved in case of a malignant lesion, because all pathways would probably be involved simultaneously because of the size, often >10 cm, of ACC at diagnosis, and considering that the lymphatic stream can be disorganized because of the tumour volume or lymph node involvement. Therefore, the extent of lymph node dissection in order to involve other stations should be considered only on the basis of pre-operative radiological evidence and intra-operative evaluation. Despite aggressive surgical resection, local and distant recurrence rate after R0 surgery remains as high as 50-80%, potentially because of the lack of an accurate identification of the nodes stations for the lymph node dissection. Indeed, nodes drain disorganization due to the high tumour volume makes impossible to predict accurately the lymphatic metastatic pathway. In this context, the rarity of ACC leads to heterogeneity of the scientific studies and consequently to the lack of perspective works, so that tumour recurrence evaluation refers to patients categories who underwent lymph node dissection with or without preoperative evidence of nodal disease