Introduction: Cancer cachexia affects many advanced non-small-cell lung cancer (NSCLC) patients. Cachexia index (CXI) was developed to assess the degree of cachexia in these patients.
Methods: Patients with metastatic NSCLC diagnosed between January 1, 2000, and June 30, 2011, at our institution were retrospectively studied. Abdominal computed tomography scans done within 1 month of diagnosis were reviewed to estimate skeletal muscle area (SMA) and skeletal muscle index (SMI) at the L3 level. CXI was developed as follows: [Formula: see text] where SMI is the skeletal muscle index, Alb is the serum albumin, and NLR is the neutrophil-to-lymphocyte ratio. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Survival among various factors was calculated using the log-rank test. Multivariate Cox regression was used to perform survival analysis in order to estimate the effects of various factors.
Results: Patients were divided into two groups around the median into stage I cachexia (CXI ≥35, n = 56) and stage II cachexia (CXI <35, n = 56). Groups did not differ in age, gender, ethnicity, or histology of cancer. Patients with stage II cachexia had significantly worse PFS (2.45 vs 5.43 months, P < 0.0001) and OS (3.45 vs 8.8 months, P = 0.0001) than those with stage I cachexia. On multivariate analysis adjusting for gender, race, and histology, patients with stage II cachexia were found to have worse PFS (hazard ratio [HR] 1.94, 95% confidence interval [CI] 1.27-2.95) and OS (HR 1.53, 95% CI 1.0009-2.34).
Conclusion: The CXI is a novel index for estimating cachexia that also correlates with prognosis in both men and women with advanced NSCLC.
Keywords: cancer cachexia; lung cancer; sarcopenia; systemic inflammation.