Oral Presentation Australian and New Zealand Obesity Society Annual Scientific Conference 2026

Intentional weight loss for colorectal cancer surgery patients with obesity using Very Low Calorie Diet: is it safe and effective? (144635)

Sally B Griffin 1 , Rainbow Lai 1 , Michelle Palmer 1 , Ian Bloomfield 2 , Vasant Rajan 2 , Lynda Ross 3
  1. Logan Hospital Nutrition & Dietetics Department, Queensland Health, Meadowbrook, QLD, Australia
  2. Logan Hospital Surgical and Critical Care Services, Queensland Health, Meadowbrook, QLD, Australia
  3. Nutrition and Exercise Sciences, Queensland University of Technology, Brisbane, QLD, Australia

Aim

Obesity increases the risk of surgical complications in colorectal cancer surgery (1-7). Preoperative very low calorie diet (VLCD) interventions have demonstrated successful weight loss and outcomes prior to a variety of non-bariatric elective surgeries (8-11). However, intentional weight loss in adults with cancer presents additional risks, and intentional preoperative weight loss has not been evaluated for safety in this patient group (10,11). This study evaluated the efficacy and safety of a dietitian-led preoperative VLCD for adults with obesity awaiting curative colorectal cancer surgery.

 

Methods

Eligible patients (adults, body mass index [BMI] ≥30, localised tumour, planned for colorectal cancer surgery, well nourished) who received dietitian-led preoperative VLCD between 2017 to 2023 were matched 1:1 with adults who did not receive VLCD (historical controls). Dietitian intervention involved dietary prescription of 800-1100kcal/day, close monitoring of bowel and nutrition impact symptoms, and regular correspondence with surgical team. Chi-squared, fishers exact and t-tests were used to compare weight change and surgical complication incidences between groups.

 

Results

Thirteen VLCD and 13 controls were eligible (median 63years, 65% male). The VLCD group had a higher BMI (+3.7kg/m2, p<0.05) but all other risk factors were well matched (p>0.05). Weight loss from baseline to surgery (median 30 days) was significantly greater in the VLCD group (-4.75kg loss, -3.8% body weight) than controls (-0.05kg, -0.06%), p<0.001. No VLCD-related serious adverse events occurred, and incidences of surgical complication were lower for the VLCD group (n=8) than control group (n=15), but this result was not statistically significant.   

 

Conclusion/ Practice implications

This study highlights that a dietitian-led preoperative VLCD can achieve clinically relevant weight loss and appears to be safe for colorectal cancer patients with obesity. This novel approach needs further exploration with larger clinical trials, and if to be used in practice, requires suitable patients, dietitian-led expertise, collaborative team approach with surgeons, and close monitoring of symptoms.

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