- Note: Nodal involvement will depend on the size of the lymph node enlargement; usually nodes of more than 2 cm are associated with malignancy. With a threshold of 1cm, false negative rates for microscopic metastases are low (4%) and false positive rates are between 3 to 43% according to the literature. Because the aim of the study will be to perform a lymph node dissection in patients with non-metastatic disease based on pre-operative evaluation, 1 cm will be the threshold used. Nodes of more than 1 cm will be considered positive and those patients will be excluded as is mentioned in the protocol. Biopsy will not be included as part of the protocol as those potential patients with nodes of more than 1 cm will be excluded.