Treatment of Liver Metastases With Electrochemotherapy (ECTJ) Phase II

The study is an extension of previously concluded and published study on electrochemotherapy of colorectal liver metastases (Edhemovic et al. JSO 2014). In this extension 15 patients will be included. Four groups of patients will be included. The patients from groups 1 and 2 are patients with up to 3 unresectable liver metastases, demanding too excessive resection, or untreatable by standard thermal ablative methods due to the close proximity of major blood vessels. Electrochemotherapy will be offered to these patients as the only treatment option. In case of multiple, both resectable and non-resectable liver metastases, the latter will be treated with electrochemotherapy, whereas other metastases will be resected or treated by RFA. These groups of patients are:

1. Patients with one to three (1-3) metachronous liver metastases of colorectal cancer, not larger than 5 cm, that are positioned in unresectable liver area, near blood vessels, but in otherwise operable patients.
2. Recurrent liver metastases of colorectal cancer, not more than 3 and not larger than 5 cm in diameter, each. For those patients any other treatment could represent unacceptable risk due to possibility of insufficient liver residual after resection or less effective radiofrequency ablation due to the proximity of blood vessels.

Groups 3 and 4 include patients with intent to cure within standard of care using two-stage surgical approach. This two-stage surgical approach will allow adding electrochemotherapy during the first operation and tissue collection for histological analysis during the second operation. Adding electrochemotherapy to these patients will not affect their treatment within standard of care recommended in the current guidelines. These groups of patients are: 3. Patients with synchronous metastases, but their general condition and extent of the disease will not allow simultaneous removal of the primary tumor and metastases. During the first operation, the primary tumor will be removed (colorectal resection) and some of the liver metastases will be treated by electrochemotherapy. About 6 weeks later, during the second operation for liver metastases, both treated and non-treated metastases will be removed with liver resection. 4. Patients with bilateral, multiple, metachronous metastases in whom standard treatment includ two-stage liver resection, due to the extent of the disease and/or their general condition. During the first operation, right portal vein will be ligated and metastases on the left side will be excised or ablated with radiofrequency ablation. At the same time, up to three metastases on the right side were treated with electrochemotherapy. During the second operation, both treated and non-treated metastases on the right side will be removed with right hemihepatectomy.

Electrochemotherapy will be offered to the patients also when they refuse standard treatment.

Depending on the position of metastases, appropriate electrodes will be selected; hexagonal needle electrodes with fixed geometry for metastases not larger than 3 cm in diameter, where their lower edge is located up to 3 cm below the liver capsule. ECT will be performed based on standard operating procedures for treatment of cutaneous and subcutaneous tumors / metastases with ECT.