Limited Effectiveness in Early Human Clinical Experience with Pulsed Electrical Field Ablation.

Purpose: To evaluate oncological outcomes, abscopal effect, and adverse events of pulsed electrical field (PEF) ablation of tumors in the chest, abdomen, and pelvis.

Materials & methods: PEF ablations performed at an academic medical center between May 2023 - January 2024 were retrospectively analyzed . 11 patients (male/female: 4/7, age:58 ± 19) underwent 11 PEF sessions targeting 13 tumors (lung metastasis from solitary fibrous tumor (n=3) and colorectal carcinoma(CA) (n=1), osteosarcoma pleural metastases (n=2), hepatocellular CA (n=2),liver metastasis from colorectal CA (n=1)and leiomyosarcoma (n=1), metastatic melanoma to pancreas (n=1), metastatic retroperitoneal lymph node from endometrial CA(n=1), recurrence of endometrial CA in vaginal cuff(n=1)) with the goal of complete coverage (n=11/13) or debulking (n=2/13). The mean tumor diameter was 1.9 ± 1.0 cm (range, 0.4 - 3.3 cm). Cross-sectional imaging follow-up was 5.3 ± 2.2 months (range, 1.9 - 7.9 months). Oncological outcomes, abscopal effect, and adverse events categorized according to SIR guidelines were reported.

Results: Of 11 tumors underwent ablation for complete coverage, complete coverage was achieved for 1 (9%) and residual detected in 9 (81%). 10 of 11 patients (91%) showed either residual, local or distant progression within a median of 3 months. No abscopal effect was observed. There were 2 mild and 2 severe adverse events.

Conclusions: PEF ablation showed a low rate of complete coverage (9%) and a high rate (91%) of residual, local or distant progression. No abscopal effect was observed within a median of 5.1 months after the ablation.