Disease control of uterine cervical cancer: Relationships to tumor oxygen tension, vascular density, cell density, and frequency of mitosis and apoptosis measured before treatment and during radiotherapy

Identification of biological parameters of major importance for the control of malignant diseases can be useful for the design of optimal treatment re gimes for individual patients. Tumor oxygen tension (pO(2)), vascular densi ty, cell density, and frequency of mitosis and apoptosis were measured befo re treatment (40 patients) and after 2 weeks of radiotherapy (22 patients) in patients with uterine cervical cancer. The aim was to investigate whethe r one of the parameters was more important for disease control than the oth ers. Three sets of data were considered; the pretreatment parameters, the p arameters measured after 2 weeks of radiation, and the changes in the param eters during this time. The pO(2) was measured polarographically; the other parameters were determined by histological analyses of tumor biopsies. Hyp oxic subvolume (HSV5), i.e., the fraction of pO(2) readings <5 mm Hg multip lied with tumor volume, showed the strongest correlation to control. Patien ts with a small HSV, before treatment had a higher control probability afte r a median follow-up time of 50 months than patients with a large HSV5 (P < 0.001). All other parameters or changes in parameters showed impaired corr elation to control compared with pretreatment HSV5. The present results sug gest that pretreatment oxygenation is more important for disease control of cervical cancer than the oxygenation after 2 weeks of radiotherapy or the changes in oxygenation during this time. Moreover, vascular density, cell d ensity, and frequency of mitosis and apoptosis before treatment or after 2 weeks of therapy are probably not as important as pretreatment oxygenation as well. Although significant correlations between disease control and some of the parameters other than pretreatment oxygenation can occur in studies based on a large number of patients, the specificity of these parameters i n the prediction of control is probably not as high as for oxygenation.