Pilot Study for High Output Drainage Removal After Gastrectomy

Inclusion Criteria: * Patients pathologically diagnosed with gastric adenocarcinoma before surgery. * Patients eligible for complete surgical resection (R0 resection). * Patients with an ASA (American Society of Anesthesiologists) score of 3 or lower. * Patients with more than 300 ml of drainage in the 24 hours on the postoperative day 4. Exclusion Criteria: * Patients aged 80 or older. * Patients with stage IV gastric cancer. * Patients with ascites due to peritoneal metastasis. * Patients with evident intra-abdominal complications following surgery. * Patients who require the insertion of additional percutaneous drainage due to insufficient drainage. * Patients who underwent incomplete gastric resection (R1 or R2 resection). * Patients diagnosed with cancers other than gastric cancer. * Patients with a history of major intra-abdominal surgery or abdominal radiotherapy that may hinder the normal absorption of intra-abdominal fluid. * Patients with more than 500 ml of drainage in the 24 hours on postoperative day 4. * Patients presenting with any of the following clinical signs or diagnoses: 1. Postoperative pancreatic fistula (POPF), defined as drain amylase levels (Drain amylase; D-amy) more than 3 times higher than serum amylase levels (Serum amylase; S-amy). 2. Fever exceeding 37.8℃. 3. Presence of any of the following clinical markers of inflammation: i. White blood cell count (WBC) \> 15,000/μL ii. C-reactive protein \> 200 mg/L 4. Observation of non-serous drainage fluid, such as: i. Chylous fluid: Milky-colored fluid. ii. Bloody or sanguineous fluid: Intra-abdominal fluid suggestive of ongoing hemorrhage. * Vulnerable subjects will not be enrolled in the study, including minors, pregnant women, neonates, adults with impaired consent capacity, individuals in institutional facilities, students, employees of medical institutions or research centers, pharmaceutical company employees, military personnel, unemployed persons, impoverished individuals, homeless individuals, terminally ill patients, or patients in emergency situations.