Abstract
BACKGROUND: Surgery is the cornerstone of treatment for colorectal cancer (CRC), and postoperative prognosis is a hot topic in CRC research. Although body mass index (BMI) is closely related to the occurrence and development of CRC, its impact on prognosis remains controversial. The purpose of this study is to explore the impact of different BMI levels on the postoperative prognosis of CRC. METHODS: Two hundred and four patients who underwent primary radical CRC surgery in the Department of Gastrointestinal Surgery of The First Affiliated Hospital of Chongqing Medical University from January 2019 to June 2019 were retrospectively collected. According to BMI, they were classified into low/normal weight (BMI <24 kg/m(2)), overweight (24 kg/m(2) ≤ BMI <28 kg/m(2)), and obese (BMI ≥28 kg/m(2)) groups. The clinicopathological features, tumor antigens, blood tests, serum biochemical indices, peripheral blood immune cell flow cytometry, recurrence/progression-free survival (RPFS), and overall survival (OS) were compared between the two groups. RESULTS: Overweight BMI emerged as an independent protective factor, markedly lowering the risk of CRC recurrence or progression [hazard ratio (HR) =0.367; 95% confidence interval (CI): 0.175-0.769] and cancer-related mortality (HR =0.273; 95% CI: 0.105-0.714). Overweight patients consequently exhibited significantly better RPFS (P=0.02) and OS (P=0.004). Peripheral CD8(+) T cell (P=0.04) and CD3(+)CD4(-)CD8(-) T cell counts (P=0.03) differed significantly across BMI groups, with both subsets markedly reduced in the peripheral blood of overweight patients. Alanine aminotransferase (ALT; P<0.001), γ-glutamyl transferase (GGT; P=0.004), bicarbonate (HCO(3) (-); P=0.004), and glucose (P<0.001) also differed among BMI groups. Postoperative course-complications and length of stay-did not differ significantly among BMI groups (P=0.70). CONCLUSIONS: Overweight patients exhibited significantly better prognosis, possibly attributable to an activated immune status and adequate nutritional reserves, suggesting that CRC patients might benefit from appropriate perioperative weight gain.