Long-term survival after percutaneous irreversible electroporation of inoperable colorectal liver metastases

Abstract

Background: For colorectal liver metastases (CRLM) that are not amenable to surgery or thermal ablation, irreversible electroporation (IRE) is a novel local treatment modality and additional option.

Methods: This study is a retrospective long-term follow-up of patients with CRLM who underwent IRE as salvage treatment.

Results: Of the 24 included patients, 18 (75.0%) were male, and the median age was 57 (range: 28-75) years. The mean time elapsed from diagnosis to IRE was 37.9±37.3 months. Mean overall survival was 26.5 months after IRE (range: 2.5-69.2 months) and 58.1 months after diagnosis (range: 14.8-180.1 months). One-, three-, and five-year survival rates after initial diagnosis were 100.0%, 79.2%, and 41.2%; after IRE, the respective survival rates were 79.1%, 25.0%, and 8.3%. There were no statistically significant differences detected in survival after IRE with respect to gender, age, T- or N-stage at the time of diagnosis, size of metastases subject to IRE, number of hepatic lesions, or time elapsed between IRE and diagnosis.

Conclusion: For nonresectable CRLM, long-term survival data emphasize the value of IRE as a new minimally invasive local therapeutic approach in multimodal palliative treatment, which is currently limited to systemic or regional therapies in this setting.

Keywords: CRLM; colorectal cancer; irreversible electroporation; liver metastases; long-term; salvage treatment; survival.

Figure 1

Kaplan–Meier survival curves based on tumor characteristics. Notes: There were no statistically significant differences comparing T- and N-stage at the time of diagnosis or number of CRLM at the time of IRE. (A) T1/2 and T3/4. (B) N0, N1, and N2. (C) One or more than one (2+) hepatic metastases. Abbreviations: CRLM, colorectal liver metastases; IRE, irreversible electroporation.

Figure 2

Kaplan–Meier survival curves based on patient characteristics. Notes: No statistically significant difference was detected between gender and age. (A) Female (F) and male (M). (B) Young (Y) and old (O) patients, split by the median.

Figure 3

Kaplan–Meier survival curves based on IRE treatment characteristics. Notes: Comparison of size of CRLM subjected to IRE and time of IRE after diagnosis, no statistically significant difference was found. (A) Size of the treated metastasis (smaller vs ≥2 cm). (B) Early (E) or late (L) IRE, split by the median. Abbreviations: CRLM, colorectal liver metastases; IRE, irreversible electroporation.