Safety and efficacy of irreversible electroporation for aggressive fibromatosis: Initial experience

Summary

Aggressive fibromatosis requires coordinated multidisciplinary care to manage. This first report explores the role of Irreversible Electroporation (IRE) in controlling the disease when conventional options are not available. A retrospective evaluation of a single center experience from 05/2012 to 08/2017 revealed 6 patients with biopsy-proven aggressive fibromatosis referred to Interventional Radiology for IRE. Three chest wall tumors, 1 thigh tumor, 1 popliteal tumor, and 3 calf tumors (total of 8 tumors) were treated with IRE (NanoKnife System, AngioDynamics). A total of 10 procedures were performed as 2 lesions were managed in stages due to size. All 8 tumors (100%) achieved a modified Choi PR (7 by tumor density, 1 by size) at a mean follow up of 124 days post-IRE, while none met criteria for RECIST1.1 PR. Five out of 8 eventually met criteria for RECIST1.1 PD with a mean time to progression (TTP) of 335 days post IRE. Four of 6 patients required additional therapy (chemotherapy or another systemic agent) after IRE due to disease progression, with a mean of 520 days until the next treatment. IRE can provide local control of aggressive fibromatosis, though a high rate of recurrence can be expected. Modified Choi criteria may be a more accurate reflection of early treatment response than RECIST1.1 as it captures changes of density when size does not reflect response.