Purpose: To determine the relationships between tumor oxygenation and nodal stage in a prospective study of patients with cervix cancer, controlling for other prognostic factors.
Methods and materials: Between 1994 and 1999, 128 eligible patients with cervix cancer were entered into a prospective study of tumor oxygenation assessed by Eppendorf oxygen electrode before primary radiation therapy. Oxygenation was evaluated using the proportion of pO(2) values < 5 mmHg (HP(5)), and tumors were classified as hypoxic if the HP(5) was > 50%. Patients were assigned to one of three groups: those with no imaging evidence of nodal (pelvic or para-aortic) or distant metastatic disease (N group; n = 67), those with equivocal findings (E group; n = 28), and those with nodal or distant metastatic disease (P group; n = 33).
Results: The proportion of hypoxic tumors in the P, E, and N groups were 67%, 50%, and 40%, respectively (p = 0.014), with median HP(5) values of 63%, 48%, and 36%, respectively (p = 0.0024). In a multivariate analysis including tumor size, stage, HP(5), and hemoglobin, it was found that tumor size and HP(5) were the only independently significant variables for the finding of metastatic disease (p = 0.009 and 0.017, respectively).
Conclusion: In this patient population, there was a significantly increased risk of nodal or distant metastases in patients with hypoxic tumors, and this finding was independent of tumor size. These results are consistent with the hypothesis that tumor hypoxia is an adverse prognostic factor associated with selection for a metastatic phenotype.