(P 449) UNDERSTANDING GAPS IN KNOWLEDGE AND PATIENT-REPORTED PAIN IN EPITHELIOID HEMANGIOENDOTHELIOMA: RESULTS FROM A GLOBAL PATIENT REGISTRY

Objective: Epithelioid Hemangioendothelioma (EHE) is an ultra-rare vascular sarcoma with an incidence of < 1 per million. EHE can occur anywhere in the body with variable spread and aggressiveness, posing challenges to diagnosis and clinical management of symptoms. We aimed to investigate (1) patient awareness of their molecular mutation subtype and (2) pain burden. These insights identify gaps in molecular subtype classification and underscore unmet needs in symptom management, illustrating opportunities to improve care and advance therapeutic discovery.

Methods: People diagnosed with EHE were informed about opportunities to join the EHE Global Patient Registry by the EHE Foundation. Participants provided eConsent. Data was collected in surveys through a secure web-based application. PROMIS® Pain Intensity and Interference instruments were utilized. Categorical variables were represented using frequency distributions and compared using the Chi-square test. A p-value < 0.05 was considered significant.

Results: Of 209 respondents of the diagnosis survey, 25% had genomic testing, whereas 19% did not and 56% were unsure if genomic analysis was done. While 16% of respondents had the WWTR1 (TAZ)-CAMTA1 mutation and 0.5% had YAP1-TFE3, 83% did not know their genomic subtype. Of 160 respondents of the pain assessment survey, 36% reported moderate to severe worst pain and 23% reported moderate to severe average pain. Pain interfered moderately to severely with daily activities (25%), work at home (24%), social activities (24%), and household chores (26%). Compared to those with localized disease, a higher percent of participants with multi-organ EHE reported moderate to severe levels of worst pain (40% vs. 30%, p = 0.2) and average pain (25% vs. 19%, p = 0.4), though statistically insignificant.

Conclusion: These findings highlight suboptimal patient awareness of molecular diagnostic results and notable pain burden in EHE. Optimizing genomic test use and patient education can improve care planning and research participant identification. Pain characterization may inform care and serve as exploratory endpoint in drug development.