Microregional blood flow in murine and human tumours assessed using laser Doppler microprobes

A multichannel laser Doppler system has been used to measure microregional fluctuations in perfusion in the HT29 human tumour xenograft and in patients with advanced malignant disease. A comparison is made with previously obtained data for the SaF, a transplantable murine tumour. The 300 μm diameter probes recorded fluctuations in erythrocyte flux in tumour microregions with an estimated volume of 10^-2 mm³. Of the 66 human tumour microregions sampled, 26% showed a change in erythrocyte flux by a factor of 2 or more over the 60 min measurement period, compared with 37% of HT29 and 48% of SaF microregions. In each of the studies more than 50% of changes were completed within 20 min, although slower changes were more common in the human tumours than in the experimental systems. Within the 1 h monitoring period at least 30% of the changes were reversed (human tumours 30%, HT29 45%, SaF 31%). These findings demonstrate that microregional changes in erythrocyte flux, consistent with transient, perfusion-driven changes in oxygenation, are a feature of human malignancies as well as experimental transplanted tumours.