THE EXFOLIATION OF FREE MALIGNANT-CELLS IN THE PERITONEAL-CAVITY DURING RESECTION OF COLORECTAL-CANCER

The presence of free malignant cells in the peritoneal cavity followin g potentially curative resection of colorectal cancer may be responsib le for some cases of local recurrence. Twenty-six patients (age 58 - 8 8 years, male:female 12:14) undergoing colorectal cancer surgery were studied-to determine frequency of occurrence of tumour cells in the pe ritoneal cavity using an immune-magnetic cell separation technique. Pe ritoneal washings were collected after opening the peritoneal cavity a nd also prior to closure. A murine monoclonal antibody specific for ep ithelial cells was added to the peritoneal washings followed by magnet ic labelled goat-antimouse antibody. The labelled tumour cells were re trieved by passing through the magnetic activated cell sorter (MACS). Tumour cells were detected in peritoneal washings from 11 patients (pr eresection only n = 0, post-resection only n = 6, and both n = 5). Fiv e of these 11 patients had potentially curative surgery. This study su pports the use of MACS in detecting free malignant cells in the perito neal cavity.