Doxorubicin eluting intra-arterial therapy for pediatric extra-abdominal desmoid fibromatoses– a promising approach for a perplexing disease

Importance: Desmoid fibromatoses (DF) are soft tissue tumors with high propensity for local invasion but no metastatic potential. They are clinically enigmatic and difficult to treat. Surgery remains the cornerstone of primary treatment but postoperative recurrence is common and tends to behave more aggressively than the primary tumor. Systemic options are widely varied and overall show marginal benefit, with the exception of doxorubicin. Doxorubicin has proven clinical benefit but its use is limited by dose-dependent toxicities.

Objective: To determine the feasibility of using doxorubicin-eluting beads (DEB-DOX) via super-selective trans-arterial embolization as a method to achieve local drug efficacy with minimal systemic exposure.

Design: Retrospective analysis of four patients treated between January 2014 and July 2017.

Setting: Single center, tertiary-care pediatric hospital.

Participants: We present the results of selective DEB-DOX in four children aged 6-17 years with recurrent or refractory DF.

Intervention: Each patient underwent a total of 1-3 DEB-DOX treatments, interspersed four months apart. In total, between 1 to 6 feeding arteries were treated per patient, with no more than two vessels embolized per session. Total cumulative bead-loaded doses administered were 27, 45, 45 and 133 mg/m². MRI scans were obtained between two to three months after each treatment and at six-month intervals following completion of treatment.

Main Outcome: Efficacy was assessed by tumor response on MRI and by patient- reported symptomatic improvement.

Results: Tumor volumes were reduced by 54% - 97% within three to twelve months. Treatment was accompanied by reduction or complete elimination of MRI T2 signal in all DFs. Symptomatic relief was accomplished within three months for all patients. A single patient experienced transient lower extremity paresthesia (CTCAE Grade I) which resolved within two months. No other adverse effects were encountered over a post treatment follow up of 6-32 months.

Conclusions and Relevance: Trans-arterial doxorubicin-eluting bead embolization should be considered for patients with DF amenable to endovascular treatment. Further study is needed to validate these first promising results.