A search for malignant cells in peritoneal fluid from patients with colorectal adenocarcinoma

Cytologic examination of peritoneal fluid aids in staging ovarian malignancies and in selecting gastric adenocarcinoma patients for intraoperative adjuvant chemotherapy. Tissue culture of peritoneal fluid could be potentially valuable in confirming cell viability and establishing sensitivity to a variety of anti-cancer agents. It also could be a more sensitive diagnostic tool than cytologic examination alone. We obtained peritoneal fluid specimens from 29 patients at the time of celiotomy: 22 had colorectal adenocarcinoma and seven were controls. Cytologic examination on a portion of each specimen produced only one positive result for malignant cells. Tissue culture of the remainder of the specimens grew cells from all but one of the patients with colon cancer; however, their morphology was similar to the fibroblasts and mesothelial cells that grew from the seven controls. We speculate that these negative results stem from the absence or reduced number of tumor cells in the specimens. Without additional refinement of our methods of specimen collection and processing, cytologic examination and tissue culture of peritoneal fluid from patients with colorectal cancer are of minimal value. Nevertheless, we believe that, with the necessary refinements, they may eventually become invaluable in the management of these patients.