Abstract 1547P
Background
Immune checkpoint inhibitors (ICIs) added to first-line small cell lung cancer (SCLC) management increases the importance of understanding baseline factors/treatment contributing to long-term survival. While reported ICI trials have focused on extensive stage disease, active trials investigate possible benefits of adding ICIs in the treatment of limited stage (LS) SCLC. Here we examine factors associated with real-world long-term survival in LS-SCLC.
Methods
Retrospective cohort study of Manitobans aged >18 years who received chemotherapy with cytologically confirmed LS-SCLC diagnosed 2004–2017. Descriptive statistics compared baseline factors and treatment by survival duration [short (<6 months [m]), medium (6-24m), long (>24 m)]. Differences were considered significant when P-values ≤0.05. Overall survival was defined as time between first treatment and death or end of follow-up (August 31, 2020). Survival was assessed using Kaplan-Meier methods and Cox proportional hazards models.
Results
Real-world analysis included 304 LS-SCLC patients. Long-term survivors made up 39.1% (n=119) of the cohort and at diagnosis were more likely to be younger, performance status ECOG 0, and have normal lactate dehydrogenase, sodium, and haemoglobin (each p<0.03). Complete/partial response for short-, medium-, and long-term survivors was 41.4%, 73.1%, and 79.8%, respectively (p<0.001). Short-term survivors were less likely to receive cisplatin and more likely to receive palliate radiotherapy (RT) or no RT. Prophylactic cranial irradiation (PCI) was used in 10.3%, 30.1%, and 64.7% of short-, medium-, and long-term survivors (p<0.001), respectively. Five-year survival was observed in 18% of patients. Cox proportional hazards modelling showed that only performance status (ECOG 1-2 HR 1.39 [1.05-1.84], ECOG 3-4 HR 1.69 [1.09-2.63]) and PCI (HR 0.45 [0.35-0.58]) were independently associated with survival. Only PCI was significant in a 6m landmarked model.
Conclusions
In patients with LS-SCLC treated with chemotherapy, 39.1% survive >24 months and 18% at least five years. Traditional prognostic factors are associated with long-term survival, with performance status and receipt of PCI having the most significant impact.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
CancerCare Manitoba and The University of Manitoba.
Funding
AstraZeneca Canada.
Disclosure
D. Dawe: Financial Interests, Institutional, Research Grant: AstraZeneca Canada; Financial Interests, Personal, Advisory Board: AstraZeneca Canada. R. Rittberg: Financial Interests, Personal and Institutional, Research Grant: AstraZeneca. I. Syed: Financial Interests, Personal, Full or part-time Employment: AstraZeneca Canada. D. Moldaver: Financial Interests, Personal, Full or part-time Employment: AstraZeneca Canada. S. Banerji: Financial Interests, Institutional, Research Grant: AstraZeneca Canada; Financial Interests, Personal, Advisory Board: AstraZeneca Canada. All other authors have declared no conflicts of interest.