Wound healing after excision of subcutaneous tumors treated with near-infrared photoimmunotherapy

Abstract

Near-infrared photoimmunotherapy (NIR-PIT) is a novel cancer therapy that employs a combination of infrared light and tumor-targeted monoclonal antibody-photoabsorber conjugates to cause both direct tumor necrosis and immunogenic cell death. NIR-PIT may have potential in the perioperative setting before surgery, and therefore it is important to know the effect of NIR-PIT on wound healing. Fifty mice were implanted with subcutaneous xenografts of N87 human gastric cancer cells, and tumors were excised after reaching a predetermined size. After excision, 30 mice were split into three groups: Controls, NIR-PIT 1 day prior to surgery and NIR-PIT 3 days prior to surgery. The quantity of reactive oxygen species (ROS) in each wound was measured on Postoperative Days 2 and 4, and mice were monitored weekly for 4 weeks for evidence of local tumor recurrence as well as clinical evidence of wound healing complications (eg, dehiscence, infection). The remaining 20 mice (10 controls, 10 treated with NIR-PIT 1 day prior to surgery) were sacrificed on either Postoperative Day 7 or 14, the skin around wounds were excised, and tensile strength was measured with a digital force gauge. There were no significant differences between treatment and control groups with respect to wound ROS levels, wound tensile strength, local tumor recurrence, or postoperative complication rates (P > .05). In conclusion, neoadjuvant (pre-operative) NIR-PIT shows no evidence of adverse wound healing effects, and it is likely a safe adjunctive treatment to surgery. Postoperative use of NIR-PIT merits investigation.

Keywords: near-infrared photoimmunotherapy; neoadjuvant; reactive oxygen species; surgery; wound healing.