The use of a panel of monoclonal antibodies can lower false-negative diagnoses of peritoneal washing in ovarian tumors

The examination of peritoneal washings is an important part of both the initial staging and follow-up of ovarian cancer. If cancerous cells have begun to spread from the ovary, they may be detected by rinsing the abdominal cavity and examining the fluid. In cases where there is no cancer spread large enough to be visible to the surgeon, these washings may provide the only indication that the cancer is advancing. Likewise, in the follow-up of patients who have already been treated for ovarian cancer, the presence of cancer cells in fluid rinsed from the abdominal cavity may provide the first indication of recurrence. The examination of the rinsing fluids is not straightforward, however. Normal cells will be recovered with this method, and even with careful examination cancerous cells may not be detected among the normal cells. A study was conducted to determine if monoclonal antibodies may be used to improve the examination of such washings. Monoclonal antibodies are highly specific and may be used to immunocytochemically stain cancer cells; the cells stained in this manner would then stand out noticeably against the background of normal cells, which stain little or not at all. Four different monoclonal antibodies were tested in the evaluation of 117 patients who were undergoing surgery for ovarian abnormalities and 121 patients who were undergoing a 'second-look' operation to observe for signs of recurrent cancer. The fluid used to rinse the abdomen was examined in the conventional way, and the cells were also stained with the monoclonal antibodies. For the patients undergoing their first surgical procedure, the traditional technique identified cancerous cells in 11 of 27 cases involving early cancer and 21 of 30 cases of advanced cancer. The antibodies, on the other hand, detected cancerous cells in the rinsing fluid in 15 of 27 early cancer cases and in 25 of 30 cases of advanced cancer. Similarly, for the patients being followed-up, traditional examination revealed cancerous cells in 39 of 121 cases while the antibodies revealed cancerous cells in 61 of 121 cases. These results indicate that the use of monoclonal antibodies to stain cells in fluid rinsed from the abdomen can increase the chances for the detection of ovarian cancer cells. (Consumer Summary produced by Reliance Medical Information, Inc.)