Abstract
BackgroundDesmoid fibromatosis (DF) is a rare fibroblastic proliferation that was historically treated with surgery. We report (a) outcomes using low‐dose chemotherapy, methotrexate (MTX), and vinorelbine (VNL) for patients with progressing disease (PD) and (b) whether tumor volume (V tumor) and T2 signal on magnetic resonance imaging (MRI) are more reflective of treatment response compared with maximum tumor dimension (D max) defined by RECIST1.1.MethodsPatients with biopsy‐proven DF, treated with MTX/VNL from 1997 to 2015 were reviewed. MRI for a subset of patients was independently re‐evaluated for response by RECIST, V tumor, and quantitative T2 hyperintensity.ResultsAmong 48 patients treated for a median 19 months MTX/VNL, only nine (19%) had previous surgery. RECIST‐based overall response rate was complete response (CR) 20 (42%) + partial response (PR) 19 (39%), stable disease (SD) 8 (17%), for a clinical benefit rate of 98%. The median progression‐free survival (PFS) was 120 months, (95%CI 84‐155 months). Thirty‐six (75%) patients had not progressed at a median 38 months from treatment completion. Most common grade 1/2 toxicities included nausea (n = 12, 25%) and fatigue (n = 9,19%) with no grade 3/4 toxicities. In 22 patients with serial MRIs, there was a decrease in D max mean by 30%, V tumor by 76%, and in 19/22 (86%) a decrease in T2 signal intensity.ConclusionLow‐dose MTX/VNL for a defined duration has high efficacy with sustained benefit and minimal toxicity for treating DF. V tumor and T2 signal might better predict treatment response than RECIST.
Highlights
Desmoid fibromatosis (DF) is a rare, benign but locally aggressive, and infiltrative fibroblastic tumor that lacks the ability to metastasize but often requires intervention due to pain and functional impairment
Treatment response by RECIST criteria may not be adequately described by the changes in largest dimension of these tumors (Dmax); we evaluated the approximate change in tumor volume (Vtumor) to assess if this method of measurement could compliment T2 imaging changes in evaluation of treatment response
T2 changes evaluated on serial magnetic resonance imaging (MRI) images from the subgroup of 22 patients were compared at interquartile ranges
Summary
Desmoid fibromatosis (DF) is a rare, benign but locally aggressive, and infiltrative fibroblastic tumor that lacks the ability to metastasize but often requires intervention due to pain and functional impairment. When there is persistent progression of DF, many expert centers currently advocate for the use of medical therapy for initial intervention.[8,9,10] there are several systemic therapeutic DF options, in the absence of comparative studies, most institutions have selected a regimen based on historical data and local experience. Other expert centers have reported their experience with MTX and vinca alkaloid regimens and a range of best response rates, from 15% to 52%,1,8,11-14 has been observed in mostly pretreated, heterogenous DF patient populations. Previous literature has described using low‐ dose chemotherapy for DF in heavily pretreated cohorts, in whom prior surgery 53%‐80% and radiation 10%‐17% were used.[8,11,14] Our study reports best response in a population minimally exposed to these prior interventions. We report one of the largest studies to date on the efficacy and toxicity of MTX/VNL in an adult DF population treated uniformly at a single institution and in a subset of patients, we report T2‐weighted signal changes based on review of serial MRI images
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