Prognostic impact of reoxygenation in advanced cancer of the head and neck during the initial course of chemoradiation or radiotherapy alone

Background. Previous studies have shown that radiation of hypoxic tumors can result in reoxygenation phenomenon. The relevance of this phenomenon for prognosis is unclear. This study analyzes whether the presence of hypoxia, or the extent to which reoxygenation occurs during the initial phase of primary chemoradiation or radiotherapy, can predict the clinical outcome in advanced tumors of the head and neck. Methods. The distribution of oxygen partial pressures was determined using pO(2) histography (Kimoc 6650, Sigma pO(2)-Histograph, Eppendorf, Hamburg, Germany). In cervical lymph node metastases of 37 patients with advanced carcinoma of the head and neck (stage IV, UICC), these values were determined before the start of primary chemoradiation or radiotherapy alone (pO(2)x). Thirty-two of 37 patients were reexamined after 1 week of therapy, and measurements were taken again in the same nodes (pO(2)y). The results obtained from these measurements were correlated with both, the initial response to therapy and follow-up results (43 months). Results. In all patients, pronounced hypoxia (median pO(2), 3.2 mmHg) was found before therapy. In 19 of 32 patients, chemoradiation/radiotherapy induced reoxygenation (DeltaO(2) = pO(2)y - pO(2)x) with median DeltapO(2) increasing to 6.5 mmHg after 1 week (p = .049). The group of patients with a complete or partial response showed only a slight increase of median DeltapO(2) (1 mmHg) compared with a strong reoxygenation effect in the group of patients with no change (mean value of median DeltapO(2) = 10.3 mmHg; p = .0062). The group of patients with DeltapO(2) values lower than median showed significantly better survival rates compared with the other group (p = .036). Conclusion. These data suggest that reoxygenation under therapy may have prognostic relevance in patients with advanced carcinoma of the head and neck treated by primary chemoradiation or radiation therapy. Remarkably, however, a poor outcome was associated with a higher degree of reoxygenation. (C) 2002 Wiley Periodicals, Inc.