(P 31) CLINICAL CHALLENGES AND EVOLVING TREATMENT STRATEGIES IN DESMOID FIBROMATOSIS: A SINGLE INSTITUTION EXPERIENCE

Objective: Desmoid tumor, also known as desmoid fibromatosis (DF), is a rare, locally proliferative tumor characterized by an overgrowth of myofibroblastic cells. Due to the varied clinical presentation of DF, there are a multitude of treatment options. This study provides our institutional experience in characterizing and treating DF as well as patient outcomes.

Methods: A retrospective review was performed for 49 patients diagnosed with DF. Patient demographics, tumor characteristics, treatment characteristics (surgery, systemic therapy, medical therapy, or embolization), and tumor recurrence were reported. We reported our institution’s treatment trends over time, relative risk analysis for surgery, as well as univariate analysis for recurrence.

Results: DF most commonly presented in the lower extremity (n=10), abdominal (n=9), and extra-abdominal areas (n=8). Thirty-seven patients received surgery with overall recurrence rate of 29.7% (11/37). In total, eight patients received medical therapy including tamoxifen/sulindac (n=5), nirogacestat (n=1), and sorafenib (n=2). Relative risk for surgery and tumor recurrence was not significantly correlated with race, gender, location, or large tumor size > 5cm. Four patients treated with medical therapy experienced tumor reduction and symptomatic improvement.

Conclusion: Management of DF includes many surgical and non-surgical options. We noted a high recurrence rate in patients who received surgical treatment and effective tumor control in patients receiving medical therapy. While surgery may be necessary for highly invasive DF, medical therapy may be equally effective as a non-invasive approach.