Follow up After completion of study therapy (which will vary by study arm) patients will be evaluated every three months during follow up for progression over a period of 18 months. Each follow up visit will include physical examination, CT or MRI imaging of the neck. Chest imaging will be obtained (or not) as indicated by standard of care. After the first 18 months, patients will be followed-up per standard of care, with documentation in the case report form (CRF) limited to progression and survival noted at their standard of care visits. If a patient should move away or otherwise be lost to in-person follow up but is amenable to telephone follow up, this will be permitted during the standard of care follow up period.