WCLC 2025 - Posters & ePosters-EP.06.05 Extensive-Stage Small Cell Lung Cancer Compared With Metastatic Extrapulmonary Small Cell Cancers- a Retrospective Study

EP.06.05 Extensive-Stage Small Cell Lung Cancer Compared With Metastatic Extrapulmonary Small Cell Cancers- a Retrospective Study

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This retrospective single-institution study compared extensive-stage small cell lung cancer (ES-SCLC) with metastatic extrapulmonary small cell cancers (EPSCC) to evaluate differences in treatment outcomes. The study included 89 adults diagnosed between 2013 and 2022: 49 with ES-SCLC and 40 with EPSCC originating mainly from gastrointestinal (GI), hepatopancreaticobiliary (HPB), and genitourinary (GU) sites. All patients had biopsy-proven disease and received systemic therapy.<br /><br />Key findings showed that median overall survival (mOS) was similar between ES-SCLC and EPSCC groups—10.5 months vs. 9.5 months, respectively (p=0.34). However, median progression-free survival (mPFS) was significantly longer in ES-SCLC (8.2 months) compared to EPSCC (6.4 months, p=0.04). Among EPSCC subtypes, the HPB cohort had the worst prognosis with mOS of 4.7 months, while GI and GU cohorts showed better survival (~11-12 months). Most ES-SCLC patients received first-line platinum-etoposide chemotherapy combined with immune checkpoint inhibitors (ICI), whereas only 4 EPSCC patients received upfront ICIs, potentially contributing to their poorer mPFS.<br /><br />The study highlights that although EPSCC and ES-SCLC share systemic disease characteristics and similarly poor prognoses, EPSCC outcomes vary by primary tumor site, with HPB primaries faring worst. The limited use of ICI therapies in EPSCC contrasts with established ES-SCLC treatment protocols validated by large trials (IMpower133 and CASPIAN), where combining chemotherapy with ICIs has demonstrated survival benefits.<br /><br />The authors conclude that EPSCC can be treated similarly to ES-SCLC but underscore the need for large prospective trials to assess whether adding ICIs improves outcomes in EPSCC. They also suggest molecular profiling may help develop prognostic markers and targeted therapies in the future.<br /><br />In summary, EPSCC shows comparable overall survival but shorter progression-free survival than ES-SCLC, with primary site significantly influencing prognosis and limited use of immunotherapy likely affecting treatment efficacy in EPSCC.

Asset Subtitle

Parikshit Padhi

Meta Tag

Speaker Parikshit Padhi

Topic Pathology and Biomarkers

Keywords

extensive-stage small cell lung cancer

metastatic extrapulmonary small cell cancers

ES-SCLC

EPSCC

overall survival

progression-free survival

hepatopancreaticobiliary cancer

immune checkpoint inhibitors

platinum-etoposide chemotherapy

molecular profiling