Percutaneous cryoablation for the treatment of extra-abdominal desmoid tumors.

Abstract

11582 Background: Management of extra-abdominal desmoid tumors (DT) has evolved over the last decade, with emphasis on conservative management based on guidelines from the Desmoid Tumor Working Group. There is growing evidence for ablative therapies, including percutaneous cryoablation (PCA), but there is little data on long-term outcomes with PCA. This large cohort study reports efficacy and long-term outcomes for patients with extra-abdominal DTs with PCA. Methods: Patients with pathologically-confirmed extra-abdominal DT were recruited consecutively at a high-volume referral center from 2014-2025. Data points including patient demographics, tumor characteristics, and procedural details for cryoablation were collected. The primary outcome was ablation success using the modified response criteria in solid tumors (mRECIST), measuring change in viable tumor along the longest tumor diameter. Secondary outcomes were change in lesion volume (TLV), complications per Clavien-Dindo classification, patient-reported symptom resolution, and progression-free survival (PFS). Results: A total of 53 patients undergoing 83 PCA procedures were identified. 67.9% of patients were female. The median follow up time was 40.1 months. Thirty-two patients were treated with PCA as first-line therapy, while 21 were treated as salvage therapy. The median change in viable tumor volume using mRECIST was -100%; 26 patients had a complete response (CR), 13 had partial response (PR), 7 had stable disease (SD), and 13 had progressive disease (PD). The median change in TLV was -71.7%. One-year and five-year PFS rates were 88.2% and 66.6% respectively. Fifty patients had symptoms including pain, an enlarging mass, or decreased range of motion prior to PCA; 94.0% had symptomatic improvement or resolution after PCA. Two patients had major complications: one inferior epigastric hemorrhage and one small bowel injury treated with a small bowel resection. Conclusions: This study provides the largest cohort of extra-abdominal desmoid tumors undergoing PCA. PCA can lead to patient-reported symptom resolution, a substantial decrease in mRECIST and TLV, and has a low complication rate. This study adds further evidence that PCA is safe and effective for treating extra-abdominal desmoid tumors.