The aim of this first-in-man study is to evaluate the safety of calcium electroporation used in patients with Barrett's esophagus high-grade dysplasia through an endoscopic system.

After being informed about the study and potential risks, all patients give written informed consent. Thereafter, patient will get calcium electroporation with biopsies and digital photographs on day 0. We expect to discharge all patients same evening. Between day 3-7 an examination is followed by gastroscopy with biopsies and digital photographs. On day 14 the patients are followed in our outpatient clinic. 6 weeks after treatment the patients will undergo endoscopic mucosa resection (EMR) or endoscopic submucosa dissection (ESD) surgery and thereby the standard care of treatment for Barrett's esophagus high-grade dysplasia.

Inclusion Criteria:

1. Male or female ≥18 years old.
2. Histological verified Barrett's esophagus high-grade dysplasia (BE HGD)
3. Expected survival > 3 months.
4. Performance status Eastern Cooperative Oncology Group (ECOG)/World Health Organization (WHO) ≤ 2.
5. Platelets ≥ 50 billion/l, International Normalized Ratio (INR) < 1.5. Medical correction is allowed, e.g. correction of a high International Normalized Ratio (INR) using vitamin K.
6. Subjects must be willing and able to comply with the procedure, such as agreed follow-up visits.
7. Sexually active men and fertile women must use adequate contraception during this trial
8. Subjects must give written informed consent.

Exclusion Criteria:

1. Coagulation disorder that cannot be corrected.
2. Subjects with a clinically significant cardiac arrhythmia.
3. Concurrent treatment with an investigational medicinal product
4. Patients with any other clinical condition or prior therapy that, in the opinion of the investigator, would make the patient unsuitable for the study or unable to comply with the study requirements.
5. Pregnancy or lactation

A medical doctor will always be responsible for final inclusion of the subject.