Predictors of Response to Chemotherapy in Patients with Advanced Non-small Cell Lung Cancer: A Prospective Cohort Study

Introduction: Lung cancer carries the highest cancer-related mortality rates worldwide. Despite all recent advances, the mortality from lung cancer is still rising. A better understanding of the risk factors may help us predict responses to chemotherapy for better management. Aim: To evaluate predictors of response to chemotherapy in advanced Non -Small Cell Lung Cancer (NSCLC) patients. Materials and Methods: This was a prospective cohort study conducted in the Department of Pulmonary Medicine at Government Medical College and Hospital, Chandigarh, India. A total of 60 confirmed cases of advanced (stage IIIB and IV) NSCLC patients were enrolled consecutively for a duration of two years. Baseline clinical parameters, routine blood tests, spirometry, exercise capacity using the 6 Minute Walk Test Distance (6MWTD), and Computed Tomography (CT)-based tumour size were recorded. Certain pre-defined patient, disease, and therapy-related factors (age, gender, dyspnoea, baseline blood tests, tumour size, histology, etc.) were evaluated for their possible role as predictors of treatment response in advanced NSCLC patients. A positive response was defined if the response to chemotherapy was Complete Response (CR) or Partial Response (PR), and a negative response if the response was Progressive Disease (PD) or Stable Disease (SD) as per revised RECIST (Response evaluation criteria in solid tumors) 1.1 criteria. Variables between the two groups were compared using the Mann-Whitney U test and Chi-square test. To find out the factors that may predict response to treatment, univariate and multivariate logistic regression analysis were used. Results: Out of a total of 60 confirmed cases of NSCLC patients, only 40 patients were able to complete the four cycles of chemotherapy. The mean age of the patients was 58.5 +/- 9.6 years. There were a total of 35 males (87.5%) and five females (12.5%) in the study. Out of 40 patients, 27 (67.5%) had squamous cell carcinoma and 13 (32.5%) had adenocarcinoma. On univariate analysis, Neutrophil-Lymphocyte Ratio (NLR) had a statistically significant association with tumour response (p<0.001). On multivariate analysis, advanced age (p=0.05) and high (>3.81) NLR (p=0.002) were found as independent predictors of poor response to chemotherapy. Conclusion: Pre-treatment high NLR and advanced age are significant factors for a poor response to chemotherapy treatment in advanced NSCLC patients.