In vivo cell kinetic measurements in human oesophageal cancer: what can be learned from multiple biopsies?

The importance of intratumour variability of cell kinetics was studied in 60 patients with cancer of the oesophagus. Five biopsies per tumour were taken. The labelling index, S-phase duration and potential doubling time (Tpot) were measured using flow cytometry. The mean Tpot value was 5.56 +/- 4.43 days (+/- 1S.D.) for adenocarcinomas and 4.40 +/- 2.45 days (+/- 1S.D.) for squamous cell carcinomas. These values were statistically significantly different. Although intratumour variation in Tpot measurements occurred, the intertumour variability was more important (P < 0.00001). This feature permits classification of tumours into slow and fast proliferating groups, leaving an intermediate group of tumours that could not be unequivocally categorised. The relative distribution of tumours into these three categories depends on the intratumour and intertumour variability of Tpot, and on the cut-off values used. Increasing the number of biopsies from one to five reduces the number of non-classifiable tumours.