Combined whole tumor cell and monophosphoryl lipid A vaccine improved by encapsulation in murine colorectal cancer.

Background Whole autologous colon cancer vaccines in combination with various adjuvants have been used in both animals and humans. At this writing, vaccine regimens have been initiated in humans 3 to 6 weeks postoperatively. This delay between tumor resection and vaccination gives surviving tumor cells an opportunity to establish themselves. Vaccine administered either preoperatively or immediately after surgery, in theory, should be more effective. However, surgery-related immunosuppression may diminish the effectiveness of preoperative or early postoperative vaccines. This problem may be overcome by limiting postoperative immunosuppression via the use of minimally invasive methods. Alternatively, the impact of the vaccine may be improved by encapsulating the vaccine, plus adjuvant, which in theory, should extend exposure time. Encapsulation of cancer vaccines in polysaccharide particles has not yet been studied. The goal of this study was to determine whether vaccine encapsulation, preoperative vaccination, and early postoperative vaccination affected the tumor burden. In addition, laparotomy and carbon dioxide insufflation were compared.