Impact of Remaining Teeth Number on Prognostic Nutritional Index in Patients Undergoing Gastrointestinal Tumor Surgery

Objectives: Malnutrition can influence perioperative complications and long-term survival in patients with gastrointestinal (GI) cancers. Oral functional decline is associated with decreased food intake, and a reduced number of remaining teeth contributes to malnutrition. However, the impact of preoperative oral conditions on perioperative nutritional status remains unclear. This study investigated the relationship between the number of remaining teeth and the prognostic nutritional index (PNI) in patients undergoing surgery for gastrointestinal malignancies. Methods: In total, 178 patients who underwent gastrointestinal surgery with perioperative oral management at our hospital between January and December 2022 were retrospectively analyzed. Data, including age, sex, tumor site, number of remaining teeth, blood test results, skeletal muscle index, and body mass index (BMI), were extracted from electronic medical records. The PNI and CRP–albumin ratio (CAR) were calculated. Correlations between the number of remaining teeth and nutritional indicators were examined. Results: The number of remaining teeth showed a significant correlation with the PNI in the upper gastrointestinal group (r = 0.336, p = 0.015) and with BMI in the hepatobiliary-pancreatic group (r = −0.519, p = 0.001), after adjusting for age using partial correlation analysis. No significant correlations were observed in the lower GI group. Conclusions: Among patients with upper GI cancer, a lower number of remaining teeth was associated with a lower PNI, influencing postoperative outcomes. Impaired oral function may affect the prognosis of patients with upper GI tumors, emphasizing the need for careful, comprehensive nutritional and oral management as part of perioperative support.