Irreversible electroporation for treating pancreatic cancer

In a registry of 200 patients with locally advanced (stage III) pancreatic adenocarcinoma (LAPC) treated by irreversible electroporation (IRE; n=50 for IRE plus resection for margin enhancement and n=150 for IRE alone), the median overall survival from the date of diagnosis was 28.3 months (range 9.2 to 85.0 months) for the resection plus IRE group (n=50) and 23.2 months (range 4.9 to 76.1 months) for the IRE alone group (n=150). The median overall survival from the day of IRE treatment for the resection plus IRE group was 23.0 months (range 8.3 to 36.3 months) and for the IRE alone group was 18.0 months (range 4.9 to 55.4 months). The median overall progression-free survival for all patients was 12.4. In a case series of 50 patients with LAPC (T4 lesions) treated by IRE for primary treatment (n=29) or margin extension (n=24), the median overall survival for all patients was 12.03 months (95% confidence interval [CI] 7.71 to 23.12). For the primary treatment group it was 7.71 months (95% CI 6.03 to 12.0 months) and overall survival was not reached in the margin-extension group (p=0.01, log rank). In a case series of 21 patients with unresectable pancreatic carcinoma without metastatic disease (TNM stage III) treated by IRE, the median survival after treatment was 10.2 months compared with 9.3 months in a matched cohort (hazard ratio=0.54, p=0.053). A propensity matched case control study compared IRE plus chemotherapy or radiotherapy (n=54) with chemotherapy or radiotherapy alone (n=85). Some patients in the IRE group also had resection at the same time as the IRE procedure (19/54 patients). There are some inconsistencies between the data in the main text, the figure, and the abstract in this paper. In the text, the authors reported that local progression-free survival in the IRE group was 14.0 months compared with 6.0 months in the comparison group, p=0.01; distant progression-free survival was 15.0 months compared with 9.0 months, p=0.02; and median overall survival was 20 months compared with 11 months, p=0.03. The figure in this paper suggests median OS in the IRE group was 17 months. The survival curves for the 2 groups overlap at 20 months. The patients who had resection with simultaneous IRE (19/54) did not have statistically significantly improved survival compared with IRE alone (35/54; 23.1 months compared with 17.2 months, p=0.1).

In the registry of 200 patients with LAPC (TNM stage III) treated by IRE plus resection for margin enhancement (n=50) or IRE alone (n=150), recurrence (defined as persistent viable tumour assessed using dynamic imaging and compared with pre-IRE scanning or tissue diagnosis) was reported in 29% (58/200) of patients. The most common site of disease recurrence was the liver (n=34), followed by lymph nodes (n=11) and the peritoneum (n=7). Local recurrence after IRE success (defined as new low density lesions of 1 cm in the IRE region even without symptoms) was reported in 6 patients. In a case series of 50 patients with LAPC (T4 lesions) treated by IRE for primary treatment (n=29) or margin extension (n=24), overall recurrence was 58% after a median follow-up of 8.69 months (range 0.26 to 16.26 months). Distant recurrence was 47% at a median of 9.20 months (95% CI 6.66 to 16.98) and local recurrence was 11% at a median of 8.60 months (95% CI 5.51 to not reached). Neither local nor distant recurrence differed statistically significantly between the primary treatment group (p=0.500, log rank) and the margin-extension group (p=0.361, log rank).In the case series of 25 patients with LAPC treated by percutaneous computed tomographic-guided IRE, after a median follow-up of 12 months, median event-free survival after IRE was 8 months (95% CI 4 months to 12 months).

In a case series of 21 patients with unresectable LAPC (TNM stage III) treated by IRE, quality of life was measured at each follow-up using the Karnofsky performance scale (range 0% to 100%, with 100 representing 'completely normal' life). Quality of life declined slowly until about 8 weeks before death, when there was a sharp decline.

The specialist advisers listed key efficacy outcomes as overall and relapse-free patient survival, local tumour control, and tumour response (complete or partial).