[DNA ploidy and cell kinetics in cancer of the rectum]

The pathological assessment of rectal cancer remained essentially unchanged for 50 years and it is based mainly on Dukes' classification and histological granding. Alternative methods of classifications have also been developed but, actually, Dukes'taging is the most important prognostic factor. The limit of Dukes' classification is the incomplete discrimination between high risk and low risk patients into the same stages. The measurements of cellular DNA content by flow cytometry is emerging as a prognostic aid in many human tumours. Authors analyze on the basis of their experience on 116 curative operations for the cancer of the rectum, the relationship between tumour's features, CEA, symptoms, recurrences, survival, type of operation and DNA flow cytometry. In 100 cases they studied the percentage of cells in "s" phase. (SPF). Samples of flow-cytometry were prepared using paraffin-embedded tumour blocks. The authors didn't find any statistically significant relation among pathological features, staging, ploidy and SPF. Recurrences rate was 16.6% in diploid tumours and 23% in no diploid (p = 0.3). In SPF < 25% it was 18.2% (p = 0.5). 5-year survival was worse in aneuploid patients (p = 0.06). Using Cox' multivariate regression analysis, ploidy has not independent prognostic significance. In conclusion authors consider ploidy a prognostic factor in rectal cancer, but not independent. However, authors conclude that flow cytometry could help in early staging of the disease, especially in preoperative diagnosis. Flow cytometry has a prognostic significance with informations on tumoral biology and could contribute to select patients for adjuvant therapy or different surgical techniques.