Abstract
BACKGROUND: As is well known, lipids play an important role in cellular metabolism and storage, and they have a significant impact on signal transduction during the growth and metastasis of cancer cells. Our study aimed to evaluate the role of the preoperative plasma lipid profile, including triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) in prognosis, and to develop nomograms to predict overall survival (OS) and disease-free survival (DFS) based on the preoperative plasma lipid profile for patients with lung adenocarcinoma (LUAD) after complete resection. METHODS: Clinical data, including preoperative plasma profile levels, were retrospectively collected and reviewed in 304 patients with LUAD who underwent radical lung resection between 2016-2017. Approval of the study protocol was obtained from the Academic Ethics Committee of Shaoxing People's Hospital, and follow-up on all patients was completed in the clinic or by telephone. The OS and DFS were assessed by the Kaplan-Meier method and the Cox proportional hazards regression model. Clinicopathological factors and preoperative plasma lipid profile factors were integrated to construct nomograms. Calibration plots and concordance indexes (C-indexes) were used to evaluate the accuracy and discrimination of the models. RESULTS: TC level was significantly related to the sex of the patient (P=0.001), history of smoking (P=0.04), and death (P=0.007), and the HDL-C level was significantly associated with sex (P=0.004), history of smoking (P=0.02), tumor recurrence (P=0.050), and death (P=0.002). TC ≤3.58 and HDL-C ≤1.01 were deemed as independent preoperative risk factors for OS, and HDL-C ≤1.01 was an independent preoperative risk factor for DFS. In the multivariate analyses involving OS and DFS, an increased TC level [hazard ratio (HR), 0.504; 95% confidence interval (CI): 0.324-0.782, P=0.002] was significantly associated with better OS. Additionally, a decreased HDL-C level was significantly associated with worse OS (HR, 0.665; 95% CI: 0.443-0.999, P=0.049) and DFS (HR, 0.619; 95% CI: 0.420-0.912, P=0.02). Preoperative plasma lipid profile factors were involved in constructing the nomograms for predicting 1-, 3-, and 5-year OS and DFS. The C-index of the final nomograms was higher than that of the tumor node metastasis (TNM) staging system for predicting OS (0.735 vs. 0.689; P=0.009). The performance of the nomograms for predicting OS (0.699 vs. 0.735; P=0.03) and DFS (0.659 vs. 0.700; P=0.002) was significantly lower when preoperative plasma lipid profile factors were excluded. These findings indicated that TC and HDL-C levels are associated with the prognosis in patients with LUAD. CONCLUSIONS: In patients with LUAD, increased TC levels may predict better OS, while decreased levels of HDL-C may predict worse outcomes for both DFS and OS. These findings may aid in the identification of high-risk patients and allow them to take necessary measures in advance.