The Relationship between Sarcopenia and Systemic Inflammatory Response for Cancer Cachexia in Small Cell Lung Cancer

Abstract

Background: The prognostic significance of sarcopenia, an important component of cancer cachexia, has been demonstrated in oncologic patients. Catabolic drivers have been suggested to be key features of cancer cachexia.

Objective: To determine the relationship between systemic inflammatory markers and CT-determined muscle mass in patients with SCLC.

Methods: Cross-sectional muscle areas were evaluated at the level of the third lumbar vertebra (L3) using baseline CT images in 186 SCLC patients. Sarcopenia was defined as a L3 muscle index (L3MI, muscle area at L3/height2) of < 55 cm2/m2 for men and of < 39 cm2/m2 for women. Systemic inflammatory markers investigated included serum white blood cell count (WBC), neutrophil: lymphocyte ratio (NLR), C-reactive protein (CRP), and albumin.

Results: Mean L3MI was 47.9 ± 9.7 cm2/m2 for men and 41.6 ± 7.0 cm2/m2 for women. Sarcopenia was present in 128 patients (68.8%), and sarcopenic patients had significant serum lymphocyte counts and albumin levels (p = 0.002 and 0.041, respectively), and higher NLRs and CRP levels (p = 0.011 and 0.026) than non-sarcopenic patients. Multivariable analysis revealed that CRP independently predicted L3MI (β = -0.208; 95% CI, -0.415 to -0.002; p = 0.048), along with gender and BMI (p values < 0.001) and performance status (p = 0.010).

Conclusion: The present study confirms a significant linear relationship exists between CT-determined muscle mass and CRP in SCLC patients. This association might provide a better understanding of the mechanism of cancer cachexia.

Fig 1. Single cross-sectional area of skeletal muscle at the third lumbar vertebrae and the level of C-reactive protein (CRP) in patients with small cell lung cancer.

(a) In a 72-year-old male patients, the CT-measured L3 muscle (blue color) index was 43.4 cm²/m² and the CRP was 11.58 mg/dL at the time of diagnosis. (b) In a 69-year-old male patients, the CT-measured L3 muscle (blue color) index was 75.0 cm²/m² and the CRP was 0.09 mg/dL at the time of diagnosis.

Fig 2. Correlation graphs between CT-determined L3 muscle index (L3MI) and inflammatory markers.