Abstract 149P
Background
Patients with desmoid tumors (aggressive fibromatosis) have several treatment options, and individual experiences are vast and varied. This analysis describes the treatment landscape for patients with desmoid tumors after diagnosis.
Methods
This is a descriptive analysis of the global, survey-based Desmoid Tumor Research Foundation (DTRF) Natural History Study using data collected from Sept 2017 to Aug 2023. Participants and/or their caregivers reported desmoid tumor diagnosis and treatment. The N values vary for these analyses due to incomplete data.
Results
Of the 383 participants who completed the treatment survey (median age, 39 years), 58% (223/383) reported having a current tumor. Among the 43% (163/383) of participants who received surgery to treat desmoid tumors, 63% (103/163) reported subsequent continued tumor growth or recurrence. Among those who responded to surgical questions, 43% (50/115) reported receiving surgery both before and after a confirmed diagnosis. Surgery was reported as the 1st-line treatment for 59% (74/126) of participants who received multiple lines of treatment. 76% (281/369) of participants received systemic therapy after diagnosis, including NSAIDS (40%), tyrosine kinase inhibitors (32%), chemotherapeutics (31%), and hormone antagonists (17%) (Table). Participants reported continued tumor growth whether they received prior treatment (43%; 92/216) or not (54%; 70/129).
Table: 149P
Systemic therapies (any line; N = 281)
| N (%) | |
| Chemotherapeutics | 87 (31) |
| Methotrexate | 32 (37) |
| Vinblastine | 26 (30) |
| Doxorubicin (or loxorubicin) | 25 (29) |
| Liposomal doxorubicin (or Doxil) | 25 (29) |
| Dacarbazine | 7 (8) |
| Vinorelbine | 6 (7) |
| Hydroxyurea | 2 (2) |
| Ifosfamide | 2 (2) |
| NSAIDs (inc. sulindac and celecoxib) | 112 (40) |
| NSAIDs (not otherwise specified) | 51 (46) |
| Sulindac | 46 (41) |
| Celecoxib | 23 (21) |
| Tyrosine kinase inhibitors | 91 (32) |
| Sorafenib | 64 (70) |
| Imatinib | 26 (29) |
| Pazopanib | 9 (10) |
| Sunitinib | 1 (1) |
| Hormone antagonists | 47 (17) |
| Antihormonal agent (eg, tamoxifen) | 41 (87) |
| Toremifene | 4 (9) |
| Anastrozole | 2 (4) |
| Gamma secretase inhibitor | 3 (1) |
| Other (eg, rituximab) | 57 (20) |
Conclusions
Surgery was the most prevalent 1st-line therapy for participants with multiple treatments, with a high rate of recurrence after surgery. No trends were reportedfor use of systemic treatments. With the FDA approval of nirogacestat for the treatment of desmoid tumors, clear guidelines for sequencing surgery and systemic therapies are needed for optimum patient care.
Clinical trial identification
Editorial acknowledgement
Writing and editing support was provided by Rebekka Harding-Smith and Jessica Warren of IQVIA with funding from SpringWorks Therapeutics, Inc.
Legal entity responsible for the study
Desmoid Tumor Research Foundation.
Funding
SpringWorks Therapeutics, Inc.
Disclosure
K.A. Mercier: Financial Interests, Institutional, Research Grant: SpringWorks Therapeutics, Inc.; Non-Financial Interests, Personal, Principal Investigator: Desmoid Tumor Research Foundation. L. Hernandez: Financial Interests, Institutional, Research Grant: SpringWorks Therapeutics, Inc.; Non-Financial Interests, Personal, Other, Executive Director: Desmoid Tumor Research Foundation. A. Lucas: Financial Interests, Institutional, Research Grant: SpringWorks Therapeutics, Inc.; Non-Financial Interests, Personal, Other, Staff Associate: Desmoid Tumor Research Foundation. T. Bell, A.B. Oton, S. Zhou: Financial Interests, Personal, Full or part-time Employment: SpringWorks Therapeutics, Inc..