Peripheral Blood Oxygen Saturation: A Non-invasive Prognostic Marker in Cancer Patients Treated with Radiation Therapy- A Pilot Study

Abstract

1. To evaluate the prognostic value of SpO2 in cancer patients 2. To correlate between daily SpO2 values and tumor response to radiation. Tumor hypoxia is an important prognostic factor in Oncology. It plays an important role in tumorogenesis, radiation resistance and tumor progression. Many invasive and in-vitro methods are available to assess the hypo-oxygenated status of tumors. We evaluated if SpO2 values measured from pulse oximetry could be used as an adjunct prognostic and predictive factor in oncology patients. Ten consecutive patients with locally advanced, non-metastatic disease were evaluated. Daily SpO2 measurements throughout the treatment and weekly haemoglobin values were noted. All patients received radical intent radiation therapy. Patients were categorised into two groups: poor SpO2 (<97mmHg) and better SpO2 (≥98mmHg). Tumour response was higher in patients with better SpO2 (≥98mmHg). Patients with poor SpO2 (<97mmHg) presented with bulkier disease at diagnosis. Role of SpO2 as a prognostic and predictive factor should be explored further with in vitro and pH studies.