8104 Background: A diagnosis of lung cancer before the age of 50 is commonly driven by oncogenic alterations and observed in patients without a history of tobacco use. Little is known about the characteristics and outcomes of individuals with young-onset small cell lung cancer (YO-SCLC). Methods: We retrospectively reviewed the charts of patients diagnosed with SCLC treated in the Indiana University (IU) Health System from 2018 to 2024. Patients were stratified by age 50 years at diagnosis of SCLC for statistical comparison of key variables and outcomes. Fisher’s exact and Wilcoxon rank sum tests were applied to categorical and continuous variables, respectively. Results: Among 416 individuals with SCLC, we identified 23 patients with YO-SCLC. The incidence of YO-SCLC was 5.5 cases per 100 cases of SCLC (95% CI, 3.7-8.2) with a median age of 47 (40-49). None of the YO-SCLC were detected by lung cancer screening (LCS), compared to 17% in the >50 cohort (Table 1). Patients with YO-SCLC are more likely to have active tobacco use but significantly less pack years, compared to >50. Majority of YO-SCLC (74%) were diagnosed with extensive-stage SCLC, analogous to >50. Extensive-stage YO-SCLC patients had similar platinum-sensitivity and PFS with platinum-based therapy with or without immunotherapy but trended to have improved median OS (24.7 vs 11.1 months, HR 1.67, 95% CI 0.88-3.15, P = 0.12). Limited-stage YO-SCLC patients were more likely to receive prophylactic cranial irradiation (PCI, 67% vs 25%, P = 0.04) but demonstrated no significant difference in PFS or OS with guideline-directed therapy, compared to >50. Conclusions: YO-SCLC represents a unique under-recognized population with trends toward improved OS, despite comparable platinum-sensitivity and PFS with chemoimmunotherapy for ES-SCLC. Such patients are currently excluded from LCS due to age. These results suggest eligibility criteria for LCS could be expanded to include individuals 20 PY) and a family history of lung cancer to increase detection of YO-SCLC. The molecular underpinnings of YO-SCLC remain to be elucidated. Investigation into the genomic and neuroendocrine subtype composition of YO-SCLC is underway. Characteristic Age 50 (n = 393) Overall (n = 416) P value Sex (female) 15 (65%) 231 (59%) 246 (59%) 0.7 Stage (ES-SCLC) 17 (74%) 257 (65%) 274 (66%) 0.5 BMI 33 (23, 38) 27 (23, 32) 27 (23, 32) 0.046 COPD 7 (30%) 207 (53%) 214 (51%) 0.052 Current tobacco use 20 (87%) 247 (63%) 267 (64%) 0.025 Pack years 30 (25, 50) 45 (30, 60) 45 (30, 60) 0.043 Eligible for lung cancer screening 0 (0%) 301 (77%) 301 (72%) <0.001 Detected by lung cancer screening 0 (0%) 68 (17%) 68 (16%) 0.021 +FH lung cancer 9 (39%) 103 (26%) 112 (27%) 0.14
Kumar et al. (Thu,) studied this question.