(O P5) Percutaneous Cryoablation: A Novel First-Line Therapy for Extra-Abdominal Desmoid Tumors

Background Desmoid tumors are benign neoplasms that may develop aggressive local invasion with high recurrence risk and significant morbidity. Percutaneous cryoablation has recently been utilized as an alternative to established therapies. The purpose of this study is to summarize our institution’s experience with first-line cryoablation for desmoid tumors. Methods A retrospective review of patients undergoing first-line percutaneous cryoablation for desmoid tumors from 2014-2019 was performed. Ablation margins were classified as A0 (complete ablation without residual enhancing disease), A2a (residual disease <15% initial tumor volume), and A2b (residual disease >15%). Response was assessed at 3 months post-procedure. Results 16 patients were included. Median follow-up was 23 mos(IQR:15-34). Median age was 39 yrs(IQR:29-64). Tumor location was truncal in 6(38%), extremity in 9(56%), and head-and-neck in 1(6%). Median pre-treatment tumor size was 7.3 cm(IQR:6.0-9.4). Intent was to treat the entire lesion in 9(56%) and debulk for alleviation of symptoms in 7(44%). Ablation margins were A0 in 5(31%), A2a in 4(25%), and A2b in 7(44%). Of patients with A0 margins, none experienced recurrence with median follow-up of 25 mos(IQR:21-52). Of those with A2 margins, 6(55%) experienced progression with median progression-free interval of 14 mos(IQR:6-20). Five (31%) developed Grade-I complications, including 1 hematoma, 3 skin blistering, and 1 neuropraxia. One (6%) developed a Grade-II complication of cellulitis. Conclusion Percutaneous cryoablation was effective in achieving local control as a first-line therapy for desmoid tumors when a complete ablation could be achieved. Reasonable local control was also achieved with incomplete ablation. All symptomatic patients experienced symptom palliation.