Comparing A-mode ultrasound and computed tomography for assessing cancer-related sarcopenia: A cross-sectional study.

Background: A-mode ultrasound (US) is a potential method for directly measuring muscle thickness in patients with cancer, but its utility remains underexplored. We aimed to evaluate the feasibility of using A-mode US to assess muscle thickness, compare it with computed tomography (CT)-derived results, and assess its ability to diagnose sarcopenia.

Methods: A cross-sectional analysis was conducted with hospitalized patients with cancer. Muscle cross-sectional area (CSA) was derived from CT scans. Biceps muscle thickness (BMT) and thigh muscle thickness (TMT) by A-mode US were assessed. BMT + TMT were also combined as an additional phenotype. Muscle strength was assessed using handgrip strength (HGS) test. Sarcopenia was defined as low muscle mass (CT- and US-derived) + low HGS.

Results: We included 120 patients (53.3% women, 45% older adults, and 85.8% with disease stages III-IV). TMT alone and the combined approach (BMT + TMT) were weak and positively correlated and significantly associated with muscle CSA, explaining 35% of CSA variability (R² = 0.35). TMT individual and combined with BMT exhibited the highest accuracy for men (area under the curve >0.70). Sarcopenia diagnosed by BMT + TMT exhibited the highest frequency (34%) and moderate agreement with CT-derived sarcopenia (κ = 0.48).

Conclusion: A-mode US has the potential to be a feasible tool for diagnosing sarcopenia in clinical practice at the bedside for patients with cancer despite the need for further improvements in the tool's accuracy. Our main findings suggest that combining measurements of BMT and TMT may enhance its clinical significance in diagnosing sarcopenia.