New research shows that intensive weight loss before colorectal cancer surgery is safe, feasible, and potentially cost-effective for patients with excess weight. The findings come from the multicenter CARE trial, which tested a low-energy total diet replacement in adults awaiting elective colorectal cancer resection.
Colorectal cancer is the third most common cancer globally and the second leading cause of cancer-related deaths, accounting for about 10% of all cases. Surgery is a standard treatment but carries a higher risk of postoperative complications, particularly in patients with obesity.
“In bariatric surgery, preoperative weight loss improves outcomes. However, the short interval between diagnosis and treatment in colorectal cancer requires an intensive approach,” said Dimitrios Koutoukidis, PhD, associate professor of Diet and Obesity at the University of Oxford. He noted that evidence on intentional preoperative weight loss in cancer patients is limited.
The assessor-blinded randomized trial, conducted from March 2023 to August 2024 at eight hospitals in England, included adults with a body mass index (BMI) of 28 or higher. Participants were randomized to either a low-energy diet replacement program or standard care. The intervention involved replacing all meals with four nutritionally complete shakes per day, totaling roughly 800 kcal and 76 g of protein. Participants received an introductory consultation, weekly follow-ups, and an exit call with a dietitian, while the control group followed standard care.
Feasibility was assessed through recruitment, retention, adherence to calls, and weight loss. Secondary outcomes included postoperative complications, symptoms, and changes in weight and fat-free mass, with long-term cost-effectiveness modeled over 30 years.
Of 150 eligible patients approached, 71 were randomized (36 intervention, 35 control). The average age was 64, 61% were male, and mean BMI was 35.4. Participants attended 85% of dietetic calls. The median time to surgery was 33 days.
Results showed 61% of intervention participants lost at least 5% of their body weight, compared with 9% of controls. Intervention participants lost an average of 6.1 kg, 4.3 kg more than controls, without significant loss of fat-free mass. Postoperative complication rates were similar (39% vs. 40%), though fecal incontinence and skin soreness improved in the intervention group. No serious diet-related adverse events occurred, and retention reached 100%. Exploratory analysis suggested that losing ≥3.2% of body weight reduced complications by 50%.
Economic modeling estimated the incremental cost-effectiveness ratio at £7,623 ($10,193) per quality-adjusted life-year, with a 61% chance of being cost-effective at the standard £20,000 ($26,742) threshold.
“An intensive preoperative weight loss intervention was safe, feasible, and likely cost-effective as part of prehabilitation before colorectal cancer surgery, with improvements in key symptoms,” the investigators concluded, noting recruitment challenges remain before a definitive trial can assess long-term outcomes.
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