Effect of Muscle Mass and Radiodensity on Postoperative Complications and Outcomes of Colon Cancer Surgery

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In a retrospective cohort study reported in JAMA Surgery, Xiao et al found that low skeletal muscle index and low skeletal muscle radiodensity were associated with an increased risk of complications and poor outcomes following surgery for colon cancer.

Study Details

The study involved data on 1,630 patients who were diagnosed with stage I to III colon cancer from January 2006 to December 2011 at Kaiser Permanente Northern California. Low skeletal muscle index (SMI) and low skeletal muscle radiodensity (SMD) levels were assessed using preoperative computed tomography images. Low SMD was defined as values < 35.5 Hounsfield units (HU) for men and < 32.5 HU for women. Low SMI was defined as values < 52.3 cm2/m2 for men who were not obese and < 38.6 cm2/m2 for women who were not obese, and as <54.3 cm2/m2 for obese men and < 46.6 cm2/m2 for obese women.

Outcome measures were defined as length of hospital stay, any complication (≥ 1 predefined complications) or major complications (Clavien-Dindo classification score ≥ 3), 30-day mortality and readmission up to 30 days postdischarge, and overall mortality. Follow-up for overall mortality was from date of diagnosis until either patient death or December 2015.

Key Findings

Women accounted for 55.6% of the cohort. The prevalence of low SMI was 46.0% in men and 40.9% in women. The prevalence of low SMD was 30.0% in men and 30.8% in women. Concurrent low SMI and low SMD were present in 17.7% of men and 18.0% of women.

  • Patients with low SMI (odds ratio [OR] = 1.33, 95% confidence interval [CI] = 1.05­–1.68) and those with low SMD (OR = 1.39, 95% CI = 1.05–1.84) had an increased risk of remaining hospitalized for ≥ 7 days after surgery.
  • Patients with low SMI (hazard ratio [HR] = 1.40, 95% CI = 1.13–1.74) and those with low SMD (HR = 1.44, 95% CI = 1.12–1.85) were at greater risk of overall mortality.
  • Patients with low SMI were at greater risk of one or more postsurgical complications (OR = 1.31, 95% CI = 1.04–1.65) and greater risk of 30-day mortality (OR = 4.85, 95% CI = 1.23–19.15).
  • Patients with low SMD were at greater risk of major complications (OR = 2.41, 95% CI = 1.44–4.04).

The investigators concluded, “Low SMI and low SMD were associated with longer length of stay, higher risk of postsurgical complications, and short-term and long-term mortality. Research should evaluate whether targeting potentially modifiable factors preoperatively, such as preserving muscle mass, could reverse the observed negative associations with postoperative outcomes.”

Jingjie Xiao, PhD, of Covenant Health Palliative Institute, St. Marguerite Health Services Center, is the corresponding author for the JAMA Surgery article.

Disclosure: The study was supported by the National Cancer Institute. For full disclosures of the study authors, visit

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