Apixaban or Enoxaparin After Head and Neck Cancer Surgery

The goal of this clinical trial is to learn if apixaban (a pill) is a safe and easier alternative to taking enoxaparin (a daily shot) to prevent blood clots after head and neck cancer surgery. It will also learn about side effects of both medicines. The main questions it aims to answer are: Can apixaban be used safely instead of enoxaparin to prevent blood clots after surgery? Do patients find apixaban easier or more satisfying to take than enoxaparin? How well do patients follow the treatment plan with each medicine? Researchers will compare 2 groups: One group will take apixaban (a pill taken twice a day) for 10 days after surgery. The other group will take enoxaparin (a shot given once a day) for 10 days after surgery. Participants will: Take either apixaban or enoxaparin starting 12-24 hours after surgery, for 10 days total Keep a medication diary and bring back unused medicine so the study team can check adherence Complete short surveys about satisfaction with their medicine Have an ultrasound of their legs to check for blood clots 11-14 days after surgery Return for follow-up visits about 40 days and 80 days after surgery for safety checks How long will participation last? About 4 months from surgery through the last follow-up visit.