Oxygenation of Mammary Tumors: From Isotransplanted Rodent Tumors to Primary Malignancies in Patients*

Abstract

The role of oxygen in tumor cell proliferation, radiosensitivity, cytotoxicity of anticancer drugs and hyperthermia treatment has been the subject of a series of investigations (for reviews see Hall, 1988; Teicher et al., 1990, Vaupel et al., 1989a; Vaupel, 1990a,b). Despite the apparent importance of tumor oxygenation, data on pO₂ values in solid tumors are mostly derived from experiments on rodents which might not necessarily reflect the variability of the clinical situation. Due to feasible techniques available now, considerable advances have been made in the past few years in the assessment of tumor hypoxia in patients (for reviews see Vaupel et al., 1989a; Vaupel, 1990a). The latter information may be most beneficial for designing specifically tailored treatment protocols (i.e., it can be used as a prognostic indicator of whether or not an individual patient would be expected to be a good candidate for a certain treatment), for assessing early tumor response to treatment, and/or for examining potentially useful tools for prediction of long-term tumor response (Vaupel et al., 1989a). In addition, the patient data obtained from systematic studies allow for the first time a direct comparison between isotransplanted animal tumors, xenografted human cancers, and primary tumors in patients. In the present study, direct pO₂ readings in isotransplanted mammary tumors in mice, xenografted human breast cancers in immunodeficient rnu/rnu-rats, and in primary malignancies in patients are compared.