Characteristics Impacting Overall Survival in Stage IV Non-Small Cell Lung Cancer Patients

Purpose/Objective(s)

Lung cancer is the leading cause of cancer related death in the US and globally. Stage IV non-small cell lung cancer (NSCLC) is considered incurable with goals of treatment including improving symptoms and prolonging life. In recent years, the addition of targeted therapy and immune checkpoint inhibitors has improved overall survival (OS) of stage IV NSCLC. We undertook this retrospective analysis to assess the impact of modern day therapy on OS of stage IV NSCLC treated in a single institution over more than a decade.

Materials/Methods

This retrospective IRB approved study was conducted using a database of stage IV NSCLC patients treated with systemic therapy or radiation at our institution between 2005 to 2018. Patient charts were reviewed to extract information on age, gender, race, year of diagnosis, treatments and survival. OS was calculated from date of diagnosis until death using Kaplan Meier estimates. The Cox proportional hazards model was used to analyze the association between OS and demographic and tumor factors, as well as treatment periods from 2005-2010, 2010-2015, and 2015-2018. Statistical analysis was performed using R (v. 4.1.2).

Results

A total of 973 adults diagnosed with stage IV NSCLC were included in this analysis. The median age was 65 years (20-97). The median follow-up (FU) of living patients was 2.87 years (0-17.5). 52.8% patients were female, 68.6% had adenocarcinoma followed by 14.9% with squamous cell cancer and 13.3% with NSCLC NOS. The majority (64.5%) of patients were Caucasian while 33.0% were African American. 59% of patients received radiation, and 62.6% received systemic therapy. 22.6% of patients were treated between 2005-2010, 36.4% between 2010-2015 and 34.24% after 2015. The median OS for the cohort was 0.84 years with 5-year OS of 9.93%. The median OS of patients diagnosed before 2010, between 2010 and 2015, and after 2015 were 8.2, 9.8, and 13 months respectively (p < 0.0001). The corresponding 2-year OS was 17.2%, 29.4% and 36.7%, for diagnosis before 2010, between 2010-2015 and after 2015. On multivariable analysis, NSCLC NOS histology (1.36, p<0.01) was significant for worse OS, while systemic therapy (0.82, p=0.006) and treatment between 2010-2015 (0.67, p<0.001) and 2015-2018 (0.49, p<0.001) were significant predictors of improved OS. Palliative radiation, age, and gender were not significant.

Conclusion

In this single institution study, the OS of stage IV NSCLC was significantly improved based on treatment between 2010-2015 and after 2015. As suggested from clinical trials, real world evidence suggests continued improvement in OS with improvement in systemic therapy and other palliative measures. Additionally, having a histology of NSCLC NOS was significant for worse OS in this study.