Flow cytometry and colorectal neoplasia.

Transformation and the behaviour of neoplastic cells of the colorectum were studied by analysing their DNA using flow cytometry. In adenoma 34 out of 269 (13%) were aneuploid while none out of 38 metaplastic polyps were aneuploid. Aneuploidy was significantly associated with established predictors of malignancy for adenomas such as size and dysplasia (p less than 0.001). In longstanding ulcerative colitis, 8 out of 12 (66.7%) colitics with dysplasia and cancer had aneuploid DNA and none of the 15 colitics without dysplasia nor cancer were aneuploid (p less than 0.001). A progression of aneuploidy was found in adenomatous dysplasia (mild 4%, moderate 18% and severe 36%), but not in cancer differentiation (well-differentiated 62%, moderately-differentiated 64% and poorly-differentiated 63%). Survivals for rectal cancer were found to be significantly influenced by ploidy, 46% for aneuploid and 67% for diploid cancer (p less than 0.001). Multiviate analysis using the Cox regression model showed that the contribution of ploidy to prognosis was independent of tumour stage and grade but its value was relatively small.