Predictive factors in advanced head and neck cancer treated by radio-chemotherapy and hypoxia modification

Abstract

6085 Background: Anemia and tumor hypoxia are known factors for resistance to radio-chemotherapy (RT-CT). In a previous report we have suggested that spinal cord stimulation (SCS) can modify tumor oxygenation and regional blood flow in head and neck cancer (HNC). The aim of the present prospective study was to test the predictive value of pO2 measurement in HNC treated by RT-CT and hypoxia modification using SCS. Methods: Twelve male patients with advanced HNC were analyzed. Stage IVb-IVa: 8–4; mean age 58 + 7.6 years (46–70). Scheduled therapy was hyperfractionated RT (120 cGy/fraction, two fractions/day, total dose 81.6 Gy) from a Co- 60 source, and tegafur 800 mg/day. SCS devices were placed before RT-CT under local anesthesia. During treatment, SCS was connected from 20–30 min before to 20–30 min after each radiotherapy session. Before treatment, they were assessed: Hemoglobin levels and tumor oxygenation pre-SCS and pos-SCS (measured by a polarographic probe system ‘pO2 Histograph‘), expressed as median-pO2, and the fraction of pO2 values less than 5 mmHg (HF5) and less than 2.5 mmHg (HF2.5). Correlations were assessed using Pearson and Spearman tests, and actuarial survival using Kaplan-Meier estimates and Log-rank test. Results: Hemoglobin levels were correlated with oxygenation pre-SCS and pos-SCS: median-pO2 (p=0.005 and p=0.011), HF5 (p=0.048 and p=0.005) respectively. Anemia was associated with more advanced stage (IVb vs IVa, p=0.022), higher HF5 pos-SCS (p=0.028) and lower disease-free survival (p=0.019). The HF2.5 pos-SCS was adversely correlated with the 2 years actuarial: disease-free survival (p=0.027), cause-specific survival (p=0.008) and overall survival (p=0.008). HF2.5 was also correlated with hematocrit (p=0.044). Conclusions: Low hemoglobin levels and anemia are associated with more hypoxic and more advanced tumors. Pre-treatment tumor hypoxia (assessed by the fraction of pO2 values less than 2.5 mmHg during-SCS) is a strong predictive factor for survival in advanced HNC. Patients with highly hypoxic tumors should be selected for more aggressive treatments. Partially supported by: Grant ‘FUNCIS: PI 31–98‘. Scientific supervision was carried out by GICOR. No significant financial relationships to disclose.