Prognostic Factors of Chemotherapy Response and Survival in Non-Small Cell Lung Cancer: Data from Real-World Practice with Limited Access to Novel Therapy

Background: Chemotherapy is a backbone treatment in advanced-stage non-small cell lung cancer (NSCLC) for non-targetable mutations and inaccessible to novel therapies. However, the data on the response rate, factors of chemotherapy response, and survival in Thailand are limited. Objective: To find the chemotherapy response rate, factors that predict chemotherapy response and survival in advanced-stage NSCLC. Materials and Methods: A retrospective cohort study was performed by including advanced-stage NSCLC patients older than 18 years old who received chemotherapy at the medical oncology unit, Sawanpracharak Hospital between July 2014 and January 2020. Demographic data, laboratory data, details of treatment, computed tomography (CT) of chest, and survival time were collected. Descriptive statistical analyses followed by univariable and multivariable were performed to determine factors associated with chemotherapy response. Kaplan-Meier survival curve was used to estimate overall survival (OS), and the log-rank test was performed to compare survival differences in each group. The univariable and multivariable Cox regression method was adopted for OS. Results: Tree hundred four chemotherapy-treated advanced-stage NSCLC were included. The chemotherapy response rate was 45.5%, and ECOG 0-1 was a favorable prognosis for chemotherapy response (OR 3.03, 95% CI 1.480 to 7.370, p=0.004). Pericardial metastasis (HR 1.833, 95% CI 1.102 to 3.215, p=0.021), liver metastasis (HR 2.05, 95% CI 1.131 to 3.201, p=0.002), non-objective response rate (ORR) for chemotherapy (HR 1.429, 95% CI 1.099 to 1.859, p=0.008) were worse prognosis factors. Obtaining second-line and third-line systemic treatment were favorable prognoses of survival in advanced-stage NSCLC (HR 0.476, 95% CI 0.348 to 0.651, p<0.001 and HR 0.247, 95% CI 0.123 to 0.494, p<0.001, respectively). Conclusion: The response rate in chemotherapy-treated advanced-stage NSCLC was 45.5%. ECOG 0-1 was an independent factor in chemotherapy response. Liver metastasis, pericardial metastasis, no subsequent treatment, and poor response to chemotherapy were worse prognosis outcomes in advanced-stage NSCLC. Keywords: NSCLC; Advanced-stage; Factor of chemotherapy response; Factor of survival