Oxygen saturation measured in vivo in bronchial tumors during bronchoscopy in patients with lung cancer using differential path length spectroscopy (DPS) correlates with survival, stage of the disease, and expression of HIF1a

Abstract

10084 Background: Tumor hypoxia is known to correlate with poor prognosis in solid cancers. In bronchial tumors direct determination of oxygen saturation is not possible and therefore indirect measures like hypoxia related proteins as HIF1a have been studied. We studied the prognostic significance on patient survival and tumor stage of microvascular oxygen saturation (StO2) measured in vivo in bronchial tumors using optical spectroscopy and compared this to HIF1a expression in bronchial biopsies. Methods: DPS is a non-invasive real-time measurement of hypoxia related parameters such as microvascular blood oxygenation (StO2) which can be used during bronchoscopy (Bard Am J Respir Crit Care Med 2005). Endobronchial tumors (12 squamous cell carcinomas, 5 adenocarcinomas, 15 large cell undifferentiated and 6 small cell carcinomas), were measured in 38 patients. In a subgroup of patients HIF1a expression was related to StO2 using linear regression analysis. Results: StO2 of bronchial tumors was predictive for patient survival. Patients with an endobronchial tumor and a saturation lower than the median value of 52% had a significant shorter overall survival than patients with a better saturated tumor. The StO2 was also related to the stage of the disease. StO2 was significantly lower in case of advanced lung tumors (stage III & IV, StO2= 44.7 ± 24.7%) in comparison with localized lung tumors (stage I&II, StO2 = 73.3 ± 12.4) (p<0.05). StO2 correlated to HIF1a expression levels (r = −0.65). Conclusions: StO2 using DPS correlates with HIF1a expression, is related to tumor stage and is a prognositc factor. This opens a new field for study of therapeutic agents in lung cancer and may also be important in the staging of lung cancer. No significant financial relationships to disclose.