Aims:

Computed tomography based measures of body composition are emerging as important prognostic markers for patients with colorectal cancer (CRC). The aim of this study was to examine the relationship between psoas muscle index (PMI), skeletal muscle index (SMI) and clinical outcomes in stage I to III CRC patients.

Methods:

This was retrospective cohort study of prospectively maintained database at Glasgow Royal Infirmary. CT image at L3 was used to assess psoas and total skeletal muscle areas and these were normalized for height 2 to calculate PMI and SMI. Patients were classified into high and low groups using published thresholds and their relationship to clinical outcomes was studied using logistic regression analysis.

Results:

In 1002 patients included, 55% were male. 13.5% had low PMI, while 50% patients had low SMI. A moderate correlation was found between psoas and total skeletal muscle areas (r=0.70, p<0.001). On univariate analysis, low PMI was associated with postoperative complications (OR, 1.36 ;95% CI, 0.94-1.96 p=0.098) and length of hospital stay (OR, 1.60; 95% CI, 1.10-2.34, p=0.014) however, on multivariate analysis, was not independently significant.

On univariate analysis, low SMI was associated with length of hospital stay (OR, 1.47; 95% CI, 1.15-1.89, p=0.002) and overall survival (HR, 2.29;95% CI, 1.47-3.58, p<0.001) and was independently associated with overall survival (HR 1.69; 95%CI, 1.06-2.67, p<0.05) .

Conclusion:

The present study shows that though both psoas muscle index and total skeletal muscle index had prognostic value, total skeletal muscle index had independent prognostic value in patients with operable CRC.