Rapid disease progression after enzyme replacement therapy interruption in a patient with cholesteryl ester storage disorder

Context: Advanced systemic mastocytosis (AdvSM) is a rare hematologic neoplasm with poor overall survival that is characterized by an accumulation of neoplastic mast cells in various tissues and organs. Although driven by KIT D816V in 95% of cases, the heterogeneous symptom presentation of AdvSM patients may contribute to a lengthy diagnostic journey. Objective: To characterize the symptomology of AdvSM patients reported by oncologists at the initial patient encounter in a community-based setting. Design: This was a cross-sectional survey study conducted from August-November 2021. Community oncologists affiliated with Integra Connect were asked to complete a structured eCRF on referral patterns, patient signs and symptoms at initial visit, approach to diagnosis, and ongoing disease management for patients they diagnosed or treated with AdvSM in the prior 24 months. Setting: Community oncology practices affiliated with Integra Connect. Results: Twenty-eight community oncologists provided data on 55 AdvSM patients. Twenty-one had managed 2 or more AdvSM patients in the previous 3 years. Mean patient age was 56 years; 55% were female. Comorbid conditions included cardiovascular disease (38%), diabetes (38%), GERD (29%), and COPD/asthma (25%). AdvSM patients were referred to participating oncologists by primary care physicians (33%), immunologists (28%), dermatologists (11%), another oncologist (11%), rheumatologists (7%), and other specialists (9%). 93% of oncologists reported bone marrow biopsy as critical in making an AdvSM diagnosis and indicated that elevated serum tryptase (64%) and detection of KIT D816V (56%) were also important factors in making the AdvSM diagnosis. Cutaneous, gastrointestinal (GI), neuropsychiatric, and musculoskeletal signs and symptoms were common. The most common symptoms reported were pruritis (65%), maculopapular cutaneous mastocytosis (62%), flushing (60%), nausea (58%), and bloating and diarrhea (52%). Allergic reactions (40%), anaphylaxis (24%), dyspnea (35%), anxiety (49%), and fatigue (62%) were also frequently reported at the initial visit. Conclusions: This study shows that AdvSM patients receiving care in a community-based oncology setting are referred to oncologists from a variety of different specialties with a range of disease-related symptoms and multitude of comorbid conditions. Improving awareness of the clinical presentation and diagnostic strategies for AdvSM patients may expedite disease recognition, diagnosis, and treatment initiation.