A prospective appraisal of preoperative body mass index in D2-resected patients with non-metastatic gastric carcinoma and Siewert type II/III adenocarcinoma of esophagogastric junction: results from a large-scale cohort

OBJECTIVE: To prospectively investigate associations of presurgical body mass index (BMI) with clinicopathological factors and its prognostic significance in radically D2-resected patients with non-metastasized gastric cancer (GC) and Siewert type II/III adenocarcinoma of esophagogastric junction (AEG). METHODS: A large prospective cohort consisting of radically-resected GC and AEG patients was analyzed. Follow-up was successful in 671 out of 700 patients, who were categorized into underweight (BMI<18.5), normal-weight (BMI=18.5-22.9), overweight (BMI=23-24.9), and obese (BMI≥25) groups according to Asian standards. BMI-associated factors were explored using multivariable logistic regression with adjustment. Cancer-specific survival analyses were conducted applying both univariable and multivariable Cox regression methods. RESULTS: Pre-operation, higher hemoglobin levels and smaller anemia proportions were observed in larger BMI groups. Higher BMI tended to be associated with higher neutrophil-lymphocyte ratios (NLRs). Patients with higher BMI had smaller tumors and more often stage I tumors, but longer surgical time and postsurgical stay. In multivariable analyses, higher hemoglobin levels, upper tumor location, poorer differentiation, and higher NLR were significantly associated with higher BMI. Overall, survival analyses revealed no significant role of BMI. However, in further stratifications after adjustment, compared to patients with normal BMI, obese patients had better survival in women, but worse in those with AEG; underweight was associated with reduced mortality risk in tumors differentiated well to moderately; overweight patients had increased death hazard when having thrombocytopenia. CONCLUSION: Overall, preoperative BMI had limited prognostic significance in operated GC patients. However, under specific conditions (e.g., female, AEG, good differentiation, and thrombocytopenia), BMI might indicate postoperative survival.