Sex-specific trends and outcomes in small cell lung cancer (SCLC) in Spain: Insights from the CLARISSE study (2019–2024).

Abstract

8092 Background: SCLC is an aggressive malignancy with poor prognosis. Although overall incidence is declining, cases among women are increasing. European projections show decreasing mortality in men but stable rates in women—except in Spain, where a +2.4% rise is expected—highlighting the need to examine sex-specific trends. Methods: CLARISSE is a multicenter, retrospective, observational real-world study conducted in Spain. Data were collected from 29 oncology departments across the country and included adult patients (≥18 years) with histologically confirmed SCLC diagnosed between January 2019 and December 2024. Baseline characteristics, treatment patterns, and survival outcomes were analyzed by sex. Results: Among 3,488 SCLC patients, 1,177 (33.8%) were women. The annual distribution of included SCLC cases remained stable over time (15.1%–17.7%), while the proportion of women increased from 29.3% to 39.2% over 6 years. Women were diagnosed at a younger age (mean 64.5 vs. 67.8 years). Active smoking was more frequent in women (68.0% vs. 54.7%, p<0.001), whereas men showed longer smoking and greater cumulative exposure, with median durations of 45 vs. 43 years (p=0.02) and median pack-years of 50 vs. 44 (p<0.001), respectively At diagnosis, 27% had limited-stage (LS) disease, more often in women (29.6% vs. 25.7%, p=0.015). Most LS patients received platinum–etoposide plus thoracic radiotherapy. In this population, 1-year overall survival (OS) was 67.9% (95%CI, 64.8-71.0%), with a median OS of 22 months (95%CI, 19.3-24.6 months); women had longer survival than men (Table 1). Systemic first-line (1L) treatment for extensive-stage (ES) consisted predominantly of platinum-based chemotherapy (95.6%; carboplatin 83.0% and cisplatin 12.6%) combined with etoposide (92.1%). Since its approval in September 2021, immunotherapy has been given to 66.3% of patients, more often to women (70.6% vs . 63.9%, p=0.013). In the population receiving 1L therapy, 1-year OS was 34.0% (95%CI, 32.1–35.9%), and median OS was 8.5 months (95%CI, 8.1–8.8). Women had longer survival (Table 1). Patients who received 1L immunotherapy had longer OS than those who did not: 10.1 months (95%CI, 9.4–10.7 months) vs. 7.2 months (95%CI, 6.6–7.7 months). Conclusions: This large multicenter SCLC cohort shows marked sex-related differences in epidemiology, stage distribution, treatment patterns and survival in Spain. Women were increasingly represented over time, diagnosed younger, and experienced longer survival in both LS and ES disease. These results support the importance of integrating sex-specific perspectives in SCLC management and research. Survival outcomes (CLARISSE study). LS-SCLC ES-SCLC Women Men Women Men 1-year OS(95% CI) 78.1%(73.1-83.1) 62.1%(58.1-66.1) 38.3%(34.9-41.7) 31.7%(29.7-33.7) Median OS (95% CI) (months) 30.1(25.4-34.7) 17.3(14.4-20.3) 9.1(8.2-9.9) 8.0(7.6-8.5)