WASH Trial: Intraoperative Lavage as a Treatment for Pancreatic Cancer

The goal of this clinical trial is to learn if a special washing treatment used during surgery can help people with pancreatic cancer live longer. The study includes adults who are having surgery for suspected pancreatic cancer or related cancers in nearby organs (called periampullary cancers). The main questions it aims to answer are: * Does the washing treatment improve overall survival (how long patients live)? * Does it improve how long patients remain cancer-free and reduce cancer recurrence or complications? The investigators will compare two types of washing treatments and standard care to see if either method improves outcomes. Participants will: Be assigned by chance (randomized) before surgery to one of three groups: * Washing with warm saltwater (saline) * Washing with sterile water * No extensive washing (standard care) Undergo their planned cancer surgery, during which the washing treatment (if assigned) will be performed right after the tumor is removed Be followed over time to monitor survival, cancer recurrence, and any side effects The investigators estimate the washing treatment could increase average survival from about 18 months to 27 months. To ensure enough patients with confirmed pancreatic cancer are included, about 845 participants will be enrolled over time.