Sarcopenia is Associated with Metastatic Burden and is a Negative Prognostic Factor in Metastatic Non-Small Cell Lung Cancer World Conference on Lung Cancer 2018
Date
09/25/2018Abstract
Background
Sarcopenia is associated with poor outcomes in patients with solid tumors. Factors affecting sarcopenia in metastatic NSCLC (mNSCLC) are not well defined. We utilized a novel computerized tomography (CT) method to measure muscle composition and evaluate its impact on metastatic disease burden and survival in mNSCLC patients.
Method
We conducted a retrospective study of consecutive adults diagnosed with mNSCLC. Demographic features, clinicopathologic variables, radiologic imaging, and outcomes data were collected and analyzed. Total, healthy, and unhealthy muscle were identified at the L3 psoas level using a previously validated novel CT method. Blinded outcomes assessments were conducted. The primary outcome was correlation between healthy muscle percentage and number of metastases. The secondary outcome was the impact of healthy muscle on overall survival. We hypothesized less total healthy psoas muscle would be associated with greater metastatic burden and worse overall survival. Analyses were adjusted for sex, age, BMI, Charlson comorbidity index, ECOG score, total psoas cross-sectional area, and weight-loss. The survival analysis was also adjusted for presence of a targetable mutation.
Result
We identified 242 patients with mNSCLC. Mean age was 65 years. Forty-seven percent were females. Two hundred thirteen (88%) were current or former smokers. Adenocarcinoma was the most common histological subtype (162,67%) followed by squamous (49,20%) and undifferentiated (18,7%). One hundred thirteen (44%) patients had oligometastatic disease, defined as 1-3 lesions, and 142 (56%) had 4 or more lesions. Eighty (33%) had brain metastases and 69 (29%) visceral. Mean ECOG was 1. Mean percentage of healthy psoas was 74% (SD: 14). Multivariate analysis demonstrated that for every 10% increase in healthy muscle, metastatic lesions decreased by 12% (RR=0.88, 95% CI 0.78-0.98, p=0.02). The odds of oligometastatic disease increased by 39% for each 10% increase in healthy muscle (OR=1.39, 95% CI: 1.06-1.79, p=0.014). Reduced percentage of healthy muscle was associated with reduced survival (median OS 8.9, 19.1, 16.3 months for <70%, 70-80%, >80% of healthy muscle, respectively, log-rank test p=0.038). This effect was preserved in the adjusted analysis, with 13% decrease in the hazard of death for every 10% increase in percent healthy muscle (HR=0.87, 95% CI: 0.75-1.0, p=0.05).
Conclusion
Greater healthy muscle at mNSCLC diagnosis is associated with lower metastatic burden and improved survival. Our novel CT method to identify sarcopenia may be useful in mNSCLC prognostication.
