Combination chemotherapy with methotrexate and vinblastine for surgically unresectable, aggressive fibromatosis

Objective: To elucidate the clinical benefit and safety of low-dose chemotherapy using methotrexate and vinblastine in patients (mostly adults) with progressive and/or symptomatic fibromatosis.Methods: Patients were enrolled if they were treated with methotrexate and vinblastine chemotherapy for recurrences after surgical excision or newly diagnosed aggressive fibromatosis that was not amenable to surgical resection at the Korea University Medical Center from May 2008 to February 2016.Results: Twenty-two patients were treated with this regimen, and 21 were eligible for safety and efficacy analysis. Eleven (52%) of 21 patients showed a documented partial response (PR), and 11 showed stable disease (SD) by the end of treatment. All the patients who achieved PR reported a significant reduction in pain and improvement in the function of the affected lesions. Median progression-free survival was not reached at the time of analysis. The most common adverse event was abnormalities of the liver transaminases (overall 84.2%). The most common grade 3 or higher toxicity was neutropenia (36.8%), but no febrile neutropenic event was observed. The elevated levels of transaminases were normalized by reducing the dose of methotrexate or delaying treatment.Conclusions: Low-dose chemotherapy with methotrexate and vinblastine for 1 year was effective and well tolerated by adult patients with aggressive, recurrent fibromatosis.