Clinical characteristics and management of long survivors in extensive stage small cell lung cancer

Abstract

Background: Extensive disease small cell lung cancer (ED-SCLC) accounts for more than 70% of new diagnoses of SCLC with a 5-year survival of 12%. A limited percentage of ED-SCLC achieved a long term survival but their clinical and biological characteristics are largely unknown. Here we reported baseline clinical characteristics and treatment sequences of a large cohort of Long Survivors ED-SCLC compared to patients with poor outcomes.

Methods: The Epidemio-Strategy and Medical Economics (ESME) lung cancer data platform is a multicenter real-life database using a retrospective data collection process. We selected ED-SCLC patients diagnosed between 2014 and 2021. Long Survivors were defined as having an overall survival (OS) ≥ 24 months. Statistical comparisons were performed by Pearson's Chi-square, and logistic regression.

Results: We identified 3150 ED-SCLC and 489 long survivors representing 13 % of the study population. mOS was 36 months (95 %CI 34 to 39) in Long Survivors and 9 months (95 %CI 8.9 to 9.4) in other patients. Compared to Short Survivors, Long Survivors were enriched in women, patients younger than 65 years-old, ECOG PS 0-1 at diagnosis less than 3 metastatic sites and never or former smokers. The C-statistic of the multiparametric model based on patient's clinical characteristics was estimated at 0.70, with a 95 % CI (0.68, 0.73). Among those patients receiving a platinum-based chemotherapy with or without immunotherapy in first-line, a prolonged survival benefit from the chemo-immunotherapy strategy was found exclusively within the Long Survivors group even thus not statistically significant (p = 0.058).

Conclusion: Long Survivors represents a small proportion of ED-SCLC characterized by a less extensive disease and better general conditions at diagnosis. This group of patients is most likely to benefit from immunotherapy in first line setting. Biological characteristics of these patients should be investigated in order to inform clinical research for new therapeutic strategies.

Keywords: Immunotherapy; Long responders; Long survivors; SCLC.