Value of Pre-operative Assessment of Rectal Cancer by Flow Cytometric DNA Analysis

Abstract

The decisions determining the type of surgery for rectal carcinoma require an exact pre-operative assessment of the tumour and its lymph mode involvement. To determine which tumour features that can predict LNM (lymph node metastases), fifty rectal carcinomas treated by conventional curative resection were studied with flow-cytometric measurement of DNA ploidy and DNA index. Routine pathology reports provided a measure of tumour size, tumour differentiation and depth of tumour invasion. 16 (32%) of the patients had LNM. Tumour size was not associated with LNM (Mann-Whitney U test, P=0.795). There was trend toward an association between poorer differentiation and LNM (X2=5.895, df=2, P=0.0525). Invasion through the bowel wall was associated with LNM (X2=6.494, df=l, P=0.011). Ploidy was not associated with LNM (X2=2.21, df=1, P=0.138), however DNA index of greater than 1.5 was significantly associated with LNM (X2=6.359, df=l, P=0.012). Furthermore, analyzing tumour DNA ploidy at the same depth of invasion, the incidence of LNM was significantly higher in aneuploid tumours than diploid tumours (X2 =9.190, df=3, P=0.027). The result of this study suggests that pre-operative FCM analysis of DNA content of rectal cancer from biopsy sample could be useful in evaluating the status of LNM, and therefore could provide important information that may determine the type of surgery