Survival outcomes in small cell lung cancer (SCLC) pre- and post-2018: A SEER-based analysis of the impact of immunotherapy advancements.

Abstract

e13878 Background: Small cell lung cancer (SCLC) accounts for 15% of all lung cancers. It was historically treated with platinum-based chemotherapy. The 2018 introduction of anti-PD-L1 marked a shift in treatment, but survival outcomes remain understudied. This study aims to look at survival outcomes before and after immunotherapy introduction. Methods: Patients diagnosed with SCLC from 2000 to 2021 were collected from the Surveillance, Epidemiology, and End Results (SEER) database. Patients were separated into two groups by year of diagnosis, either pre-immunotherapy era (2000-2018) and post-immunotherapy integration (2018-2021). Additional demographics and clinical variables were collected. Cox regression analysis was performed to assess for associations with diagnosis before or after the 2018 immunotherapy era. Logistic regression compared variables associated with post-immunotherapy introduction. Results: A total of 100,224 patients were included. Overall one-year survival was 59.9%. One-year survival from 2000-2017 was 60.2%, while it was 57.2% from 2018-2020 (p < 0.001). However, on Cox regression survival outcomes were improved in the immunotherapy era (p < 0.001, HR = 0.931). Females (p < 0.001, HR = 0.878), household income greater than $50,000 (p < 0.001, HR = 0.952), receipt of surgery (p < 0.001, HR = 0.421), chemotherapy (p < 0.001, HR = 0.389), or radiation (p < 0.001, HR = 0.647), Black (p < 0.001, HR = 0.901), Hispanic (p < 0.001, HR = 0. 914), and Asian (p < 0.001, HR = 0.860) populations had improved survival. Worse survival was associated with age 75+ years old (p < 0.001, HR = 1.364) and regional (p < 0.001, HR = 1.771) or distant staging (p < 0.001, HR = 3.422). On logistic regression analysis, increased odds of diagnosis during the immunotherapy era were associated with females (p < 0.001, OR = 1.061), patients 60-74 (p < 0.001, OR = 1.430) and 75+ years old (p < 0.001, OR = 1.261), Black (p < 0.001, OR = 1.140), Hispanic (p < 0.001, OR = 1.184), and American Indian/Alaska Native populations (p < 0.001, OR = 1.512), household income > $50,000 (p < 0.001, OR = 1.171), and chemotherapy (p = 0.009, OR = 1.033). Conclusions: The one year survival was initially lower, possibly due to aging populations. However, adjusted data shows survival outcomes improved for the 2018-2021 cohort which correlated with the introduction of immunotherapy. Future research should evaluate strategies to combat disparities associated with worse survival.