Growth kinetics of Kaposi's sarcoma

Abstract

This is a study of cell kinetics in nodular and florid (fungating) Kaposi's sarcomas. One or more tumours from 9 patients were examined at the Uganda Cancer Institute. The very variable clinical doubling time was assessed by direct measurements of tumour diameters, and an average obtained. The mitotic count, rate of entry of cells into mitosis and cell cycle time were measured in biopsy material, and use to estimate the potential doubling time. From the difference between the potential and the actual doubling times, the rate of cell loss and the cell loss factor were calculated. The average actual clinical doubling time was slightly, but not significantly, higher for growing nodular tumours than for florid tumours. Some nodular tumours were similar to those reported in the literature for other human malignacies. Kinetic studies of static and regressing human tumours have not been reported previously. The rate of cell production found in this tumour is lower than the values reported in the literature for other malignancies. The calculated mitotic duration is long, but similar to previously reported values. The cell loss factor is high: in the static tumours it is 1.0, and in the regressing tumours greater than 1.0. In regressing tumours, the rate of cell loss was 30% higher than the rate of cell production. These tumours did not differ histologically from nearly florid tumours which were increasing in size. It is postulated that regression is determined by local vascular or mechanical factors, supplemented possibly by delayed hypersensitivity responses in some patients.