Microregional fluctuations in perfusion within human tumours detected using laser Doppler flowmetry

Purpose: Transient fluctations in erythrocyte flux consistent with perfusion driven hypoxia have been previously reported using experimental tumour models. The present study was designed to establish whether such changes are a common feature of human tumours. Methods and Materials: A multi-channel laser Doppler system was used to monitor microregional changes in flow in human tumours. Eight individual tumours were investigated, two primary and one locally recurrent breast carcinoma, two metastatic skin deposits and three metastatic lymph nodes. Six custom designed microprobes (diameter of 300 am), each monitoring a nominal sampling volume of approximately 10(-2) mm(3) were inserted into the tumour and perfusion monitored over a period of 60 min. Results: The results show that in 54% of the regions monitored there was a change in microregional blood flow by a factor of 1.5 or more. Over the whole 60-min period, 19% of the changes were reversed, with a time course of 4-44 min. Conclusions: This finding demonstrates that microregional fluctuations in perfusion occur frequently in human tumours. Furthermore, the observation that 19% of the changes were reversed implies that at least some of the cells are subject to transient acute hypoxia.