The diagnostic delay signature in rare gynecologic cancers: Assessment of emergency presentation, acute organ failure, and failure-to-rescue.

e23143 Background: Rare gynecologic cancers lack standardized diagnostic pathways and are underrepresented in trials. Rarity may generate a reproducible inpatient “diagnostic delay signature,” reflected by altered admission pathways, acute organ failure at presentation, and adverse rescue outcomes. Methods: A survey-weighted analysis of the National Inpatient Sample (NIS), 2016–2023, evaluated adult hospitalizations for rare gynecologic cancers (vulvar C51, vaginal C52, gestational trophoblastic neoplasia [GTN] proxy O01/O02/C58/D39.2) versus common gynecologic cancers (endometrial C54–C55, cervical C53, ovarian C56). Overlap admissions and palliative encounters (Z51.5) were excluded. The diagnostic delay signature included nonelective admission and acute organ failure at presentation (sepsis A40/A41 or R65.2/R57.2, shock R57, respiratory failure J96/J80, acute kidney injury [AKI] N17). Outcomes included in-hospital mortality, ICU escalation (mechanical ventilation or shock), complication burden, failure-to-rescue, length of stay (LOS), cost, routine discharge, and hospital dependence. Results: The cohort included 215,343 unweighted admissions, representing 1,076,715 hospitalizations nationally. Rare gynecologic cancers accounted for 14.1% (95% CI 13.9%–14.3%) and common cancers for 85.9% (95% CI 85.7%–86.1%). Rare-cancer distribution was GTN 8.6%, vulvar 4.4%, and vaginal 1.2%. Rare cancers had lower nonelective admission rates than common cancers (61.5% vs 67.2%; 95% CI 60.8%–62.1% vs 66.7%–67.6%) and lower acute organ failure at presentation (13.2%, 95% CI 12.8%–13.6% vs 29.7%, 95% CI 29.4%–30.0%), including lower rates of sepsis (5.6% vs 10.2%), shock (0.6% vs 1.4%), respiratory failure (3.7% vs 8.4%), and AKI (7.3% vs 19.6%). ICU escalation was less frequent (1.4% vs 3.0%), with shorter LOS (3.14 vs 5.30 days) and lower costs ($12,036 vs $20,108). In-hospital mortality was 0.56% (95% CI 0.48%–0.65%) for rare cancers versus 1.97% (95% CI 1.90%–2.04%) for common cancers. Complication burden (23.4% vs 47.4%) and failure-to-rescue mortality (2.18%, 95% CI 1.86%–2.56% vs 3.78%, 95% CI 3.65%–3.92%) were lower in rare cancers. Routine discharge was more frequent (80.1%, 95% CI 79.6%–80.7%), highest in GTN (96.9%, 95% CI 96.6%–97.2%). Among rare cancers, acute organ failure increased from 10.2% in 2016 to 16.3% in 2023, while mortality remained low. Adjusted analyses showed lower odds of inpatient mortality (aOR 0.37, 95% CI 0.31–0.45) and failure-to-rescue (aOR 0.65, 95% CI 0.54–0.77). Conclusions: Rare gynecologic cancers comprised 14% of inpatient gynecologic cancer hospitalizations and showed rising acute organ failure at presentation over time. Despite increasing acuity, rare cancers were associated with lower inpatient mortality, ICU escalation, complication burden, and failure-to-rescue.