What are your indications for including the contralateral neck when planning postoperative primary and ipsilateral elective neck radiotherapy for a well lateralized buccal squamous cell carcinoma?   

The 2019 ASCO guideline suggests contralateral neck radiotherapy for T3-T4 oral tongue and/or floor of mouth primary sites or tumors approaching midline (Koyfman, J Clin Oncol 2019). A buccal-specific retrospective series reported only 2% contralateral neck failure, including subgroup analysis of N2 and ECE (Lin, Int J Radiat Oncol 2008). For a T1 tumor not close to midline, would a combination of other risk factors (e.g., 5 positive ipsilateral nodes, ECE, largest node size over 4 cm, recurrence in the ipsilateral neck within 3 months of initial buccal surgery) push one to including the contralateral neck?