Do you routinely cover level IA lymph nodes for advanced BOT tumors extending into floor of mouth or oral tongue?  

Generally speaking, I would cover any draining nodal region that is at risk based upon the involved mucosal subsite(s). If IA is at risk because of anterior oral cavity disease involvement, I would not omit coverage simply for the fact that the primary originated in another location. 

No. Having published the outcomes of almost 500 patients treated at UF, we rarely see failures in IA nodes. 

The lymphatic drainage of the tongue is complex. Lymphatics from the tip of the tongue travel to the submental lymph nodes. This can be ipsilateral or bilateral depending on the site of the lesion. Lymph from the medial anterior two-thirds of the tongue travels to the deep cervical lymph nodes, and ...