Oxygenation of squamous cell carcinoma of the head and neck: Comparison of primary tumors, neck node metastases, and normal tissue

Background: Most previous oxygenation measurements of head and neck tumors have mainly been performed in neck nodes. We investigated, therefore, the relationship between the pO₂ status of primary tumors, cervical neck node metastases and normal tissues. Patients and Methods: 30 patients with histologically proven advanced stage III-IV squamous cell carcinoma of head and neck underwent pretreatment polarographic PO₂ measurements with a PO₂ histograph (Eppendorf, Hamburg, Germany). We obtained data on oxygenation of 23 primary tumors, of 22 neck node metastases, and of 30 contralateral sternocleidomastoid muscles. In 15 cases, we were able to perform measurements in all three regions in the same individual. results: A highly significant correlation existed between the median pO₂ of primary tumors and their neck node metastases (p = 0.0001), as well as between the proportion of pO₂ values ≤2.5 mmHg and ≤5.0 mmHg (p = 0.0001, p = 0.001) in both anatomic sites. The average pretreatment median pO₂ was 14.7 mmHg (range 0.2-58.5 mmHg) in primary tumors, 13.7 mmHg (range 1.9-50.3 mmHg) in neck node metastases, and 43.8 mmHg (range 20.8-67.7 mmHg) in sternocleidomastoid muscles. In all cases, the oxygenation of malignant tissue was below that of the corresponding muscle. There was also a weak, but significant, correlation between hemoglobin level and the median pO₂ of the primary tumors, as well as between hemoglobin concentration and the proportion of values below 5 mmHg at the primary site (p = 0.017, p = 0.003). Conclusions: Primary tumors and their regional lymph node metastases in advanced squamous cell carcinoma of the head and neck show comparable patterns of oxygenation in terms of the median pO₂ and the proportion of hypoxic measurements. This report suggests that, in patients with such carcinomas, the oxygenation data obtained at one site are related to tumor oxygenation at other sites, so that measurements in any anatomic site would be sufficient to estimate a tumor's oxygenation status. The weak correlation between pO₂ and hemoglobin level requires further investigation.