OXYGENATION PREDICTS RADIATION RESPONSE AND SURVIVAL IN PATIENTS WITHCERVIX CANCER

Background and purpose: Hypoxia appears to be an important factor in p redicting tumor relapse following radiation therapy. This study measur ed oxygenation prior to treatment in patients with cervix cancer using a polarographic oxygen electrode to determine if oxygenation was an i mportant prognostic factor with regard to tumor control and survival. Materials and methods: Between May 1994 and June 1997, 74 eligible pat ients with cervix cancer were entered into an ongoing prospective stud y of tumor oxygenation prior to primary radiation therapy. All patient s were evaluated with an Eppendorf oxygen electrode during examination under anesthesia. Oxygenation data are presented as the hypoxic propo rtion, defined as the percentage of pO(2) readings of <5 mm Hg (abbrev iated as HPS). Results: The HPS ranged from 2 to 99% with a median of 52%. With a median follow-up of 1.2 years, the disease-free survival ( DFS) rate was 69% for patients with HPS of less than or equal to 50% c ompared with 34% for those with HP5 of >50% (log-rank P = 0.02). Tumor size above and below the median of 5 cm was also significantly relate d to DFS (P = 0.0003) and patients with bulky hypoxic tumors had a sig nificantly lower DFS (12% at 2 years) than either bulky oxygenated or non-bulky oxygenated or hypoxic tumors (65%, P = 0.0001). Conclusions: Hypoxia and tumor size are significant adverse prognostic factors in a univariate analysis of disease-free survival in patients with cervix cancer. A high risk group of patients with bulky hypoxic tumors have a significantly higher probability of relapse and death. (C) 1998 Else vier Science Ireland Ltd. All rights reserved.