Comprehensive management of microscopic residual disease in colorectal cancer

Abstract

Although cancer resection has been of great benefit to patients with colorectal cancer, an unrecognized flaw that has caused the death of countless patients das not been confronted. Aithough the surgeon has dealt successfully with the primary tumor, he has neglected to treat microscopic residual disease. Cancer cells left behind within the abdomen and pelvis are responsible for the death of 30-50% of the patients who succumb to this disease and is responsible for devasting quality of life consequences that result from intestinal obstruction caused by cancer progression at the resection site and on peritoneal surfaces.Optimized surgical techniques for colorectal cancer removal minimize the microscopic residual disease that may result from surgical trauma. New developments in exposure, hemostasis, adequate lymphadenectomy and qualitatively superior margins of excisions have reduced the incidence of cancer persistence. Clinical data shows that a 40% improvement in survival with an optimization of resection techniques is possible.Not only should the surgical event for primary colorectal cancer be optimized, but also knowledgeable management of peritoneal carcinomatosis should be pursued. Resection site recurrence and peritoneal seeding can be prevented through the use of perioperative intraperitoneal chemotherapy in patients at high risk of persistent microscopic residual disease. These are patients with a performed bowel wall by cancer, positive peritoneal cytology, ovarian involvement, tumor spill during surgery and adjacent organ involnement.Patients with established peritoneal carcinomatosis can be salvaged with an approximate 50% long-term survival with knowledgeable and timely use of peritonectomy procedures, intraperitoneal chemotherapy and patient selection factors. Peritonectomy procedures employing lasermode electrosurgery allow the removal of all visible peritoneal surface cancer with an acceptable surgical morbidity (25%) and mortality (1.5%). Heated intraoperative intraperitoneal chemotherapy using mitomycin C, in addition to early postoperative intraperitoneal 5-fluorouracil, will eradicate exposed microscopic cancer seeding in a majority of patients. The Peritoneal Cancer Index which quantitates colorectal cancer carcinomatosis by distribution and by implant size must be used in the selection of patients whomay benefit from these advanced surgical oncologic treatment strategies. The goal must be complete cytoreduction for the Completeness of Cytoreduction Score is the most powerful prognostic indicator in this group of patients. The data clearly shows that there are no long-term benefits unless a complete cytoreduction combined with intraperitoneal chemotherapy occurs.Coclusions are as follows :Proper techniques for the resection of primary disease, peritonectomy procedures for the removal of all visible peritoneal implants, intraoperative and early postoperative chemotherapy for the eradication of microscopic residual disease, and quantitative tools for proper patient selection are necessary for the surgical treatment of patients with colorectal cancer.