“…It is known that the prognosis of dogs having metastatic spread of primary lung tumors to regional intrathoracic lymph nodes is poorer than in dogs without lymph node metastasis (McNiel et al, 1997;Ogilvie et al, 1989;Paoloni et al, 2006;Polton et al, 2008;Sabattini et al, 2012). Recommendations have been made that the regional intrathoracic lymph nodes are to be surgically biopsied during a lung tumor resection, but without specific guidance (Fossum, 2007;Laksito et al, 2010;McNiel et al, 1997;Paoloni et al, 2006;Rebhun and Culp, 2013). In some studies of canine lung tumors, tracheobronchial lymph nodes were not biopsied if they appeared to be of normal size, though lymph node size is not indicative nor correlative for metastasis (Lansdowne et al, 2005;McNiel et al, 1997;Paoloni et al, 2006).…”