A systematic review and meta-analysis assessing the impact of body mass index on long-term survival outcomes after surgery for colorectal cancer

• Published in: European journal of cancer (1990) Vol. 172; pp. 237 - 251
• Main Authors: Simillis, Constantinos, Taylor, Beth, Ahmad, Ayesha, Lal, Nikhil, Afxentiou, Thalia, Powar, Michael P., Smyth, Elizabeth C., Fearnhead, Nicola S., Wheeler, James, Davies, Richard J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.09.2022; Elsevier Science Ltd
• Subjects: Body mass; Body mass index; Body size; Body weight; Cancer surgery; Colon; Colon cancer; Colorectal cancer; Colorectal carcinoma; Impact analysis; Literature reviews; Meta-analysis; Obese; Overweight; Patients; Subgroups; Surgery; Survival; Systematic review; Underweight; Body mass index; Obese; Surgery; Underweight; Colorectal cancer; Systematic review; Survival; Meta-analysis
• ISSN: 0959-8049; 1879-0852
• DOI: 10.1016/j.ejca.2022.05.020

The impact of body mass index (BMI) on long-term survival outcomes after colorectal cancer surgery is debated. A systematic literature review and meta-analysis was performed to compare long-term survival outcomes of patients of different BMI categories after colorectal cancer surgery. Of the 2588 articles screened, 56 articles met the inclusion criteria, reporting on 72,582 participants. Patients with BMI <18.5 had significantly worse overall survival [hazard ratio (HR) 1.91; P < 0.0001], cancer-specific survival (HR = 1.91; P < 0.0001), disease-free survival (HR = 1.50; P < 0.0001) and recurrence-free survival (HR = 1.13; P = 0.007) compared to patients with a BMI of 18.5–25. There was no significant difference between those with BMI 25–30 and 18.5–25 in overall survival, cancer-specific survival, disease-free survival and recurrence-free survival, except for the subgroup of patients with colon cancer where patients with BMI 25–30 had significantly improved overall survival (HR = 0.90; P = 0.05) and disease-free survival (HR = 0.90; P = 0.04). Patients with BMI >30 had significantly worse disease-free survival (HR = 1.05; P = 0.03) compared to patients with a BMI of 18.5–25, but no significant difference in overall survival, cancer-specific survival and recurrence-free survival. Patients with BMI >35 compared to 18.5–25 had significantly worse overall survival (HR = 1.24; P = 0.02), cancer-specific survival (HR = 1.36; P = 0.01), disease-free survival (HR = 1.15; P = 0.03) and recurrence-free survival for colon (HR = 1.11; P = 0.04) and rectal (HR = 4.10; P = 0.04) cancer. Being underweight (BMI < 18.5) or class II/III obese (BMI > 35) at the time of colorectal cancer surgery may result in worse long-term survival outcomes, whereas being overweight (BMI 25–30) may improve survival in a subgroup of patients with colon cancer. Optimising BMI may preoperatively improve long-term survival after surgery for colorectal cancer. •Assess the impact of body mass index (BMI) on survival after colorectal cancer surgery.•Systematic review and meta-analysis performed based on 56 studies (72,582 patients).•Underweight (BMI < 18.5) or class II/III obese (BMI > 35) have worse long-term survival.•Overweight (BMI 25–30) patients have improved survival after colon cancer surgery.•Optimising BMI preoperatively may improve long-term survival outcomes.