Abstract
Desmoid tumors are classified as borderline malignancies and are characterized by a high rate of local recurrence despite the absence of distant metastasis. Low-dose methotrexate combined with vinblastine, known as the methotrexate and vinblastine (MV) regimen, has been reported as an effective treatment for desmoid-type fibromatosis (DF). At our institution, we adopt a treatment strategy beginning with celecoxib as the first-line therapy, escalating to the MV regimen only in cases showing disease progression. This study evaluates treatment outcomes based on this protocol. At our institution, 10 patients diagnosed with DF between 2003 and 2025 received surgical resection and/or pharmacotherapy. The standard approach involved initiating treatment with oral celecoxib; if no clinical improvement was observed, therapy was escalated to the MV regimen. Treatment response was assessed using Response Evaluation Criteria in Solid Tumors 1.1 criteria. Of the 10 cases, 1 achieved complete response, 5 showed partial response, 2 maintained stable disease, and 2 exhibited progressive disease, yielding a response rate of 60%. Among patients treated with the MV regimen, extended dosing intervals did not lead to tumor progression, and sustained suppression was observed in several cases. No grade 3 or 4 adverse events were reported. Celecoxib and the MV regimen appear to be effective and well-tolerated options for DF. Given its low toxicity and favorable tolerability, celecoxib should be considered the first-line treatment, especially since tumor control was achieved in half of the cases. Although tumor progression occurred in the remaining cases, disease control was subsequently achieved by introducing the MV regimen. These findings support recent trends favoring nonsurgical management and suggest that the celecoxib followed by the MV regimen strategy should be considered a primary therapeutic approach.