Exfoliated cells and in vitro growth in colorectal cancer.

Cells exfoliated from colorectal cancers may only be implicated in local recurrence if they are proven to be viable and capable of growth. Thirty patients with primary colorectal cancer were studied. Cells were obtained from primary tumour, uninvolved mucosa, mesorectum, lumen of the bowel, luminal mucus, serosal surface of the bowel and from washings of the tumour bed after dissection. Colonies grew in vitro in monolayer culture from 21/30 primary tumours; 11/41 mesorectum specimens; 11/27 luminal washings; 14/29 luminal mucus specimens; 1/27 serosal surface washings and 3/13 post-dissection washes. Colonies stained positively for the epithelial markers cytokeratin and desmosomes and also for carcinoembryonic antigen. Cells capable of in vitro growth are present in these various sites and, if spilled at operation, may well be implicated as one of the factors leading to local recurrence.