Establishment of a desirable dose using neutral argon plasma to eradicate miliary peritoneal implants: A phase I/II controlled trial.

Introduction: Neutral argon plasma (NAP) system could meet the requirements to achieve oncological cytoreduction of peritoneal carcinomatosis with miliary lesions, minimizing the associated morbidity. This phase I/II trial aims to establish the desirable dose that is safe and effective in eliminating tumor cells with lower penetration.

Methods: Patients diagnosed with different origins for peritoneal carcinomatosis and miliary implants were selected for the study. The safe and potentially effective dose (desirability) of NAP was evaluated according to three factors: distance (mm), application time (s) and power (%), to evaluate the response variables such as the presence of tumor cells (Y/N) and the depth of penetration.

Results: Ten patients and 120 samples were evaluated and treated with NAP. There was no vascular or organ injury intraoperative using a pre-established dose of 100% (coagulation mode) at a distance of 2-3 cm. The distance was found to be correlated with the presence of the tumor cells in ex-vivo analysis, with an OR of 15.4 (4.0-111.4). The time and energy used were protective factors to eliminate tumor cells with an OR of 0.4 (0.1-0.9) and 0.8 (0.8-0.9), respectively. The safest and most effective desirability results were as follows i) energy 80% during 2-4 s with a distance of 2 cm (0.89), and ii) energy 100% during 2-4 s with a distance of 3 cm (0.90).

Conclusions: The use of NAP during a CRS and HIPEC is safe and effective for eradicating tumor cells on the peritoneal surface at suggested doses of energy, distance and duration.

Trial Identification: ClinicalTrials.gov Identifier: NCT04904042.