Trends in immunotherapy use and survival impact in stage IV non-small cell lung cancer.

Abstract

e20715 Background: Lung cancer is the leading cause of cancer-related mortality in the United States and worldwide. 5-year survival rate for metastatic non-small cell lung cancer (NSCLC) is estimated at 4%. For patients who lack a driver mutation, platinum based chemotherapy had been the cornerstone treatment, but the addition of immunotherapy has altered the treatment landscape for many advanced NSCLC patients. Immunotherapy, with or without chemotherapy, has been demonstrated in many clinical trials to extend survival in both the first-line setting as well as subsequent lines of therapy. While the clinical trial data over the past several years has been robust, less is known about how these agents have fared in routine clinical practice. To understand this better, we utilized the National Cancer Data Base (NCDB) to examine the survival of patients who received immunotherapy for stage IV NSCLC. Methods: We queried the NCDB from 2004-2015 for patients with stage IV NSCLC treated with chemotherapy and at least 3 months of follow-up. Multivariable logistic regression was used to determine predictors of immunotherapy use. Multivariable cox regression was used to determine predictors of overall survival. A propensity score was calculated and used to mitigate indication bias. Results: Of 203,069 eligible patients, 5,877 received immunotherapy. The median age was 65 years (40-90). The median follow up was 10.6 months (3-154). Patients were more likely to receive immunotherapy if they were younger, had a lower comorbidity score, received treatment at an academic facility, had adenocarcinoma histology, private insurance, Caucasian race, and a more recent treatment year. The use of immunotherapy rose steadily across the dataset years, rising from 1% to 12%. Predictors of survival were younger age, lower comorbidity score, lower grade tumor, treatment at an academic facility, higher education, higher income, private insurance, metropolitan location, immunotherapy use, adenocarcinoma histology, and more recent year of treatment. On propensity-matched Kaplan-Meier analysis patients treated with immunotherapy in addition to chemotherapy had improved survival, 13.7 months compared to 11.8 months, p < 0.0001. Conclusions: This analysis demonstrates improved overall survival in stage IV NSCLC patients who received immunotherapy. There are inherent limitations of retrospective analyses of data from large databases, however the survival improvement noted in this study is concordant with the more robust prospective clinical research published to date.