Pathological Response to Perioperative FLOT in Gastric Adenocarcinoma

Perioperative chemotherapy with the FLOT regimen (5-fluorouracil, leucovorin, oxaliplatin and docetaxel) is a standard treatment for resectable gastric and gastroesophageal junction adenocarcinoma. However, real-world studies have reported lower pathological complete response rates than the pivotal trials, and Colombian evidence is limited, coming mainly from surgical series focused on operative outcomes. This descriptive retrospective study will review the medical records of adults with stage I to III gastric or gastroesophageal junction adenocarcinoma who started perioperative FLOT at Fundación Santa Fe de Bogotá (Bogotá, Colombia) between January 1, 2021 and December 31, 2025 (approximately 90 patients). It will describe pathological response (tumor regression grade by the Mandard system and pathological complete response), grade 3-4 toxicity, dose modifications, treatment adherence and completion, recurrence and overall survival. The investigators will not assign or modify any treatment, and no hypothesis testing will be performed.

Inclusion Criteria: * Patients older than 18 years with histologically confirmed stage I, II or III adenocarcinoma of the stomach or gastroesophageal junction. * Initiation of perioperative FLOT chemotherapy at Fundación Santa Fe de Bogotá between January 1, 2021 and December 31, 2025. * Sufficient clinical and treatment information to classify the patient and evaluate at least one study outcome (pathological response, toxicity, treatment adherence and completion, recurrence or vital status). Exclusion Criteria: * Metastatic (stage IV) disease documented at initial diagnosis, before starting perioperative FLOT. * Gastric or gastroesophageal junction tumors of non-adenocarcinoma histology (for example, lymphoma, gastrointestinal stromal tumor or neuroendocrine carcinoma). * Lack of the minimum information required for classification (no record of the FLOT regimen received, of clinical or pathological stage, or of at least one assessment of the primary outcome). * Oncology follow-up performed exclusively outside the institution, without adequate traceability of postoperative and long-term outcomes.