C65-11 Higher Mortality Despite Less Severe PE: The Paradox of Lung Cancer - Associated Pulmonary Embolism

Abstract Rationale Pulmonary embolism (PE) associated with malignancy carries increased mortality, but data specific to lung cancer (LC)-associated PE remain limited. We hypothesized that LC-associated PE is characterized by higher in-hospital mortality and lower utilization of reperfusion therapies compared with non-lung cancer (NLC) PE. Methods We conducted a retrospective cohort study using the 2019-2022 National Inpatient Sample to identify adult (≥18 years) hospitalizations for acute PE via ICD-10 codes. Admissions were stratified by the presence of LC, including small-cell and non-small-cell subtypes.The primary outcome was in-hospital all-cause mortality. Secondary outcomes included rates and timing of mechanical ventilation, PE subclassification (saddle, cor pulmonale, single/multiple subsegmental), reperfusion interventions (mechanical thrombectomy MT, catheter-directed thrombolysis CDT, systemic thrombolysis ST), and palliative care involvement. Multivariable logistic regression was used to calculate adjusted odds ratios (aOR) controlling for demographics and comorbidities. Results Among 755,094 PE admissions, 3.5% (n = 26,655) had concurrent LC. Compared with NLC admissions, LC patients were older (69.1 vs 63.6 years), had higher Charlson comorbidity scores (5.9 vs 2.0), longer hospital stays (5.4 vs 4.4 days), and were more often White (75.8% vs 69.9%; all p0.005).In-hospital mortality was higher in LC vs NLC (7.4% vs 3.2%; aOR 1.19, 95% CI 1.10-1.40). LC patients more often required mechanical ventilation (3.3% vs 2.8%) and had longer time to intubation (4.8 vs 2.3 days; all p0.005). Use of reperfusion therapies was significantly lower in LC: MT (2.0% vs 4.7%), CDT (0.24% vs 0.71%), and ST (1.0% vs 3.2%). LC patients also had fewer saddle PE (5.3% vs 11.1%) and cor pulmonale (6.6% vs 11.7%), but more subsegmental PE (7.9% vs 6.5%). Palliative care involvement was higher (16.8% vs 4.0%; all p0.005). Conclusions The increased mortality in lung cancer - associated PE occurred despite lower rates of massive or high-risk PE phenotypes, suggesting that underlying malignancy, comorbidity burden, and treatment limitations rather than clot severity drive outcomes. LC admissions demonstrated less frequent use reperfusion therapies, possible a combination of elevated bleeding risk, clinician selection bias away from invasive procedures, and greater emphasis on palliative management. This pattern highlights the importance of early multidisciplinary evaluation to guide risk-benefit-balanced treatment decisions. When reperfusion is deferred, timely symptom-directed and palliative care engagement should be prioritized. Systems-level efforts are needed to identify LC-PE phenotypes most likely to benefit from advanced therapy and to develop cancer-specific PE management pathways that minimize both undertreatment and unnecessary intervention. This abstract is funded by: None