Endoscopic Calcium Electroporation in Gastric Tumors (GASTRIC-CaEP)

Study Design This is a prospective, multicenter, non-randomized, non-pharmacological interventional study with longitudinal follow-up designed to evaluate the efficacy and safety of endoscopic calcium electroporation (CaEP) for the management of tumor-related gastrointestinal bleeding in patients with gastric cancer.

Participants will undergo two scheduled sessions of endoscopic calcium electroporation. The second treatment session will be performed 4 weeks after the initial procedure unless a clinical or technical contraindication arises.

Patient recruitment and follow-up are planned from JUNE 2026 through May 2028. Data analysis and dissemination of results will take place between June 2028 and December 2028.

Study Population Adult patients (≥18 years) with histologically confirmed gastric cancer presenting with iron-deficiency anemia and/or gastrointestinal bleeding attributable to the primary tumor will be prospectively enrolled after providing written informed consent.

The study will be conducted in the Gastroenterology Departments of participating hospitals.

Sample Size Based on previously published data suggesting a 90% improvement in quality of life and reduction in transfusion requirements following calcium electroporation, a clinically meaningful improvement of 20% was assumed. Using a two-sided alpha error of 0.05 and a statistical power of 80%, the required sample size was calculated as 25 evaluable patients. Allowing for an anticipated 10% loss to follow-up, the target enrollment is 28 participants.

Intervention Procedures Baseline Assessment

Before treatment, participants will undergo:

• Clinical evaluation and medical history review.
• Symptom assessment, including pain evaluation using a visual analogue scale (VAS).
• Quality-of-life assessment using the EORTC QLQ-C30 questionnaire.
• Nutritional assessment, including anthropometric measurements and laboratory testing.
• Complete blood analysis, including hemoglobin, hematocrit, albumin, prealbumin, iron studies, vitamin levels, electrolytes, and metabolic profile.
• Endoscopic tumor assessment with photographic documentation and tumor size estimation.

Tumor biopsies, non-tumoral gastric mucosal biopsies (when technically feasible), and peripheral blood samples will be collected before the first treatment and again prior to the second treatment at week 4.

Calcium Electroporation Procedure The procedure will be performed on an outpatient basis under deep sedation with standard monitoring and supplemental oxygen.

Following endoscopic evaluation of the lesion, intratumoral calcium gluconate (220 mM; 9 mg/mL) will be injected using a 23-gauge needle. The administered volume will be calculated according to the European Standard Operating Procedures of Electrochemotherapy (ESOPE) guidelines and adjusted to tumor size.

Electroporation will then be performed using the EndoVE® device connected to the distal end of the endoscope and the ePORE® pulse generator. Electrical pulses will be delivered to cover the entire tumor surface whenever technically feasible. Procedural parameters, including treated tumor percentage, number of pulses, impedance, and applied voltage, will be recorded.

After treatment, patients will remain under observation for 60-120 minutes for monitoring of immediate adverse events, including pain, bleeding, nausea, or perforation.

Follow-up A telephone safety assessment will be conducted 1 week after each treatment session.

The second CaEP treatment will be performed 4 weeks after the first procedure and will include repeat clinical assessment, laboratory evaluation, and biological sample collection.

Subsequently, patients will undergo monthly follow-up visits (in-person or by telephone, according to clinical status) to record bleeding episodes, transfusion requirements, hospital admissions, and clinical outcomes.

From month 3 onward, follow-up assessments will occur every 12 weeks (weeks 12, 24, 36, and 48) and will include:

• Clinical evaluation.
• Laboratory testing.
• Symptom assessment.
• EORTC QLQ-C30 quality-of-life questionnaire.
• Upper gastrointestinal endoscopy.
• Computed tomography (CT) imaging. Additional CaEP treatments may be offered in cases of recurrent tumor-related bleeding or anemia after exclusion of alternative causes. Retreatment may be considered in patients experiencing a decrease in hemoglobin of ≥2 g/dL from previous assessments or clinical evidence of recurrent gastrointestinal bleeding.