The Efficacy and Safety of a Preoperative Dietitian-Led Very Low Calorie Diet Clinic for Adults With Obesity for Colorectal Cancer Surgery: A Retrospective Cohort Study.

[BACKGROUND] Obesity increases the risk of complications in colorectal cancer surgery. While preoperative very low calorie diet (VLCD) interventions may provide weight loss prior to various surgeries, no data on preoperative VLCD in colorectal cancer surgery exist. This retrospective cohort study therefore aimed to evaluate the efficacy and safety of a dietitian-led preoperative VLCD clinic for adults with obesity prior to colorectal cancer surgery.

[METHODS] Patients who received the VLCD clinic intervention between 2017 and 2023 were matched 1:1 with adults who did not receive VLCD clinic intervention (controls). Primary outcome was efficacy, measured as ≥ 3% weight change from baseline to surgery. Secondary outcome was safety, measured via occurrence of adverse and serious adverse events during VLCD clinic intervention. Descriptive and clinical data were collected from medical charts. Chi-squared, Fisher's exact and nonparametric tests were used to compare data between groups.

[RESULTS] Thirteen VLCD and 13 controls were recruited (age (median(IQR) 63(59-69)years, 65% male). Baseline descriptors were similar, including planned surgical procedure, age and co-morbidities (p > 0.05). However, VLCD participants were ~9 kg heavier (median(IQR) 114.1(104.5-131.7)kg) at baseline than controls (p < 0.05). The VLCD group lost median 4.75 kg (3.8%) (p < 0.05), with 67% achieving ≥ 3% body weight loss from baseline to surgery (median(IQR) 30(18-47) days). No VLCD-related adverse events occurred. The VLCD and control groups experienced eight and 15 surgical complications, respectively.

[CONCLUSION] A dietitian-led preoperative VLCD clinic intervention achieved weight loss and appears safe. This novel approach may be useful for the preoperative optimisation of colorectal cancer patients with obesity.