Abdominal and intra-abdominal fibromatoses: Outcomes over time

Abdominal wall and intra-abdominal fibromatoses are locally aggressive, nonmetastasizing neoplasms. Surgery has been the mainstay of local control, but new forms of therapy have been developed that may influence the clinical course and morbidity. We studied the clinical features and outcomes of patients with abdominal and intra-abdominal fibromatoses over time.

Ninety-one patients-46 with abdominal wall and 45 with intra-abdominal fibromatosis-treated in our hospital systems between 2009 and 2023 were included. The patients were allocated to 1 of 2 groups based on the year of their initial treatment: before and including 2016 vs 2017-2023. Medical records and available histologic slides were reviewed.

Forty-six patients were treated between 2009 and 2016, and 45 patients were treated between 2017 and 2023. Patient ages ranged from 1 to 85 years (median, 39 years), and most patients (70%) were women (2:2 men to women). Patients self-reported as Hispanic (49%), followed by White (28%), Black (20%), and Asian (3%). A subset (21%) had familial adenomatous polyposis (FAP)/Gardner syndrome. Individuals with intra-abdominal fibromatoses (37%) were more likely to have FAP than individuals with abdominal wall fibromatosis (4%) (P < .0001). The most common initial treatment before and during vs after 2016 was surgical excision (78% and 51% respectively; P = .02), followed by active surveillance with other medical intervention (9% and 18%, respectively; P = .28) and use of tyrosine kinase inhibitors (0% and 18%, respectively; P = .014). The rate of multivisceral transplant in patients with FAP/Gardner syndrome was 47% vs 4% in patients with sporadic disease (P < .001); most transplants (92%) were performed before and during 2016. The overall tumor recurrence/persistence rate in patients who had undergone surgery was 31%. The recurrence/persistence rate in patients treated before and during 2016 was 39% (median follow-up, 24 months), which fell to 13% (median follow-up, 18 months) in individuals treated after 2016 (P = .032). The overall recurrence/persistence rate in patients with FAP/Gardner syndrome was 64% vs 21% in patients with sporadic disease (P = .002). In patients with sporadic disease, there were recurrences in 29% of patients treated before and during 2016 and in 9% of patients treated thereafter (P = .086). Intra-abdominal vs abdominal wall lesions in patients with FAP and in patients with sporadic disease were more likely to recur (26% vs 10% and 16% vs 5%), but this occurrence did not reach statistical significance (P = .15). Most recurrent tumors were treated by surgical re-excision in both groups.

Our data suggest that a combination of less morbid surgical approaches and the addition of nonsurgical approaches (active disease surveillance, use of tyrosine kinase inhibitors and other interventions) have resulted in substantially fewer surgical interventions over time for intra-abdominal and abdominal wall fibromatoses treated between 2009 and 2023. The overall probability of recurrences, however, in patients treated surgically remains similar.