Abstract
OBJECTIVES: This retrospective study investigated prognostic factors in advanced non-small cell lung cancer (NSCLC) with bone-only metastasis, and developed a graded prognostic assessment (GPA) model to estimate patient survival. METHODS: The primary endpoint was overall survival. We investigated the patients with advanced NSCLC with bone-only metastasis at the initial diagnosis and diagnosed between 2013 and 2019 in our hospital. A log-rank test and Cox proportional hazards model were used to examine factors. A GPA model was developed in the training set based on the factors that were determined significant according to their hazard ratios and verified by the validation set. RESULTS: We finally included 220 patients for analysis. These patients were divided into two groups, 147 cases for the training cohort and 73 for the validation cohort. The following were significant independent prognostic factors, and were included in the GPA model: smoking; EGFR (epidermal growth factor receptor) sensitive/ALK (anaplastic lymphoma kinase) mutations; loss of weight; hypoalbuminemia; and primary site treated by surgery or radiotherapy. GPA score of nil was assigned to smoking, without sensitive mutations, loss of weight, hypoalbuminemia, and without local treatment of primary site; the corresponding superior alternatives were scored 1.5, 2.0, 1.5, 1.5, and 1.5, respectively. The median survival times of patients with GPA scores of nil to 3.0, 3.5 to 6.0, and 6.5 to 8.0 were 14.2, 29.5, and 56.6 months in the training set (P < 0.001) and 15.2, 31.2, and 54.0 months in the validation set (P < 0.001). CONCLUSION: The survival time of patients with NSCLC with bone-only metastasis was dramatically influenced by the presence of the determined prognostic factors. The GPA model developed in this study may be a useful clinical tool to estimate the life expectancy of these patients, and guide treatment.