Non-equilibrium atmospheric pressure plasma (NEAPP) has attracted attention in cancer therapy. We explored the indirect effect of NEAPP through plasma-activated medium (PAM) on pancreatic cancer cells in vitro and in vivo. In this study, four pancreatic cancer cell lines were used and the antitumor effects of PAM treatment were evaluated using a cell proliferation assay. To explore functional mechanisms, morphological change and caspase-3/7 activation in cells were also assessed. Furthermore, reactive oxygen species (ROS) generation in cells was examined and N-acetyl cysteine (NAC), an intracellular ROS scavenger, was tested. Finally, the antitumor effect of local injection of PAM was investigated in a mouse xenograft model. We found that PAM treatment had lethal effect on pancreatic cancer cells. Typical morphological findings suggestive of apoptosis such as vacuolization of cell membranes, small and round cells and aggregation of cell nuclei, were observed in the PAM treated cells. Caspase-3/7 activation was detected in accordance with the observed morphological changes. Additionally, ROS uptake was observed in all cell lines tested, while the antitumor effects of PAM were completely inhibited with NAC. In the mouse xenograft model, the calculated tumor volume on day 28 in the PAM treatment group was significantly smaller compared with the control group [28±22 vs. 89±38 (mm3 ± SD), p=0.0031]. These results show that PAM treatment of pancreatic cancer might be a promising therapeutic strategy.

Plasma-activated liquids may represent a novel therapeutic method for the treatment of peritoneal metastases in gastric cancer.

Our study demonstrated the antitumor effects of PAL in vitro and in vivo. Intraperitoneal administration of PAL may be a novel therapeutic option for peritoneal metastases.

CY+ status is not clinically equivalent to gross peritoneal metastasis in patients with pancreatic cancer. Curative resection is still recommended regardless of CY status.

Introduction In laparoscopic gastrectomy, a method to locate the margin of an early‐stage cancerous lesion that is invisible from the serosal surface and impalpable during laparoscopic procedures is needed to determine an appropriate transection line. We conducted a prospective study to develop a new marking method using preoperative submucosal injection of indocyanine green (ICG). Methods Patients undergoing laparoscopic gastrectomy for T1 gastric cancer were recruited. The first 11 patients comprised the learning set and the subsequent 18 patients the validation set. ICG was endoscopically injected in the submucosal layer of the stomach approximately 1 cm away from the tumor edge 1 or 3 days before surgery. The diameters of the visualized ICG were compared with those of a conventional marking method using India ink in 10 historical controls. Results In the learning set, the optimal amount of ICG was determined to be 0.1 mL at a concentration of 0.5 mg/mL. In the validation set, the same procedure was repeated. No technical problems or adverse reactions related to ICG injection were observed. In all cases, ICG was successfully detected, and negative surgical margins were pathologically confirmed. The mean long diameter of the visualized ICG fluorescence measured at the mucosal surface of the stomach was significantly smaller in the current study than in the historical controls in whom India ink was used (21 vs 52 mm, P < 0.0001). Conclusions The preoperative submucosal ICG marking was safely performed and successfully detected without excessive blurring during laparoscopic gastrectomy.