Three different computed tomography obesity indices,two standard methods,and one novel measurement,and their association with outcomes after colorectal cancer surgery

Abstract

Background

Obesity can be measured by different indices, either as body mass index (BMI) or by more intuitive radiological measurements, and obesity has been shown to have an impact on outcome after colorectal cancer (CRC) surgery.

Purpose

To investigate whether the thickness of the subcutaneous adipose tissue (SAT) in the abdominal wall can be used as a surrogate for the visceral fat area (VFA)—both measured on computed tomography (CT)—in prediction of short- and long-term outcomes after elective CRC surgery.

Material and Methods

Preoperative CT scans of all patients having elective CRC surgery (stages I–III), in two consecutive years at a single-center institution, were used to measure the SAT (mm) and VFA (cm²). BMI was calculated for each patient. The three different obesity indices were used in different analyses in order to predict postoperative complications and overall survival.

Results

A BMI >30 kg/m² was an independent prognostic factor in postoperative complications (odds ratio 3.2, 95% confidence interval [CI] 1.43–7.03). SAT and VFA were not able to predict complications. Patients considered visceral obese according to a high VFA (>130 cm²) had poorer survival (hazard ratio 1.53, 95% CI 1.00–2.36) compared to non-obese patients, but in the adjusted model, VFA lost its predictive power. BMI and SAT were not able to predict mortality.

Conclusion

The novel measurement of the thickness of SAT in a preoperative setting before elective CRC surgery cannot predict either postoperative complications or overall survival; the other obesity indices had better predictive features.