Oxygenation of mammary tumors as evaluated by ultrasound-guided computerized-pO2-histography.

The average pO2 in breast carcinomas in situ is significantly lower than that in the normal breast tissue. The mean pO2 value for benign breast tumors is significantly higher than that of the breast cancers but lies significantly lower than the corresponding normal breast. No significant differences are found in the mean pO2 values when comparing cancers of different stages and histology. A decrease in the mean pO2 value is measured from the periphery to the center of the breast tumors investigated. The average pO2 values for pre- and postmenopausal patients differ significantly. The described method provides a reliable assessment of tissue pO2 in situ with a minimum of discomfort. Due to extensive inter tumor heterogeneity, prediction of pO2 values for tumors of same stage and same histology is not possible, so that measurement of individual tumor is mandatory for determining therapy response.