Postoperative fever is a common clinical finding following gastrointestinal (GI) oncologic surgery, with reported incidence rates ranging from 14% to 91%, depending on the type of procedure and patient population. While fever in the immediate postoperative period is often benign and self-limiting, it can also be an early indicator of serious complications such as anastomotic leaks, intra-abdominal abscesses, or surgical site infections. In oncologic patients, however, the interpretation of postoperative fever is particularly complex due to the interplay of cancer-related inflammation, immunosuppressive therapies, and altered physiological responses. These factors necessitate a more nuanced diagnostic approach to avoid both under- and over-treatment [1,2,3].

Patients undergoing GI cancer surgery often present with unique immunological and metabolic profiles that influence their postoperative course. Immunosuppression—whether due to chemotherapy, malnutrition, or the tumor itself—can mask typical signs of infection, making fever one of the few early warning signs of complications. Additionally, tumor-related fever, driven by cytokine release or necrotic tumor tissue, may mimic infectious processes without an underlying microbial cause. This overlap complicates clinical decision-making, as standard fever workups may yield inconclusive results. Therefore, distinguishing between benign postoperative fever, infection, and tumor-related inflammation is critical for timely and appropriate management in this vulnerable population [1,2,3].