A Proof-of-principle Study of Hyperbaric Oxygen as a Radiosensitizer Prior to Stereotactic Radiosurgery for Brain Metastases
Inclusion Criteria:
- Metastatic brain tumor referred to radiation oncology for treatment
- Size of the presenting metastatic lesion up to 4.5 cm diameter
- Age > 18 years
- Patients must give informed consent indicating they are aware of the investigational
nature of this treatment
- Karnofsky Performance Status > 70% (Zubrod score 0 to 1)
- Women of childbearing potential must have a negative serum or urine pregnancy test
prior to start of study therapy
Exclusion Criteria:
Patients with the following conditions are not eligible to participate in this trial:
- Pregnant women or women of childbearing potential without adequate contraception
- Evidence of pneumothorax
o Untreated pneumothorax risks tension pneumothorax during ascent in HBO chamber
- COPD with C02 retention
o Such patients can develop respiratory depression as HBO reduces their hypoxemic
drive
- Uncontrolled seizure disorder
o Note that patients on adequate antiepileptic medications may receive HBO
- Claustrophobia resistant to medication
o Pre-medication with anxiolytics is generally sufficient for almost all anxious
patients undergoing HBO treatment
- History of middle ear surgery o Failure to equalize pressure in the middle ear can
cause displacement of middle ear structures with consequent hearing loss
- History of bleomycin administration
o HBO can exacerbate interstitial pneumonitis in such patients
- Current cis-platinum chemotherapy (i.e. therapeutic levels in the bloodstream at the
time of HBO therapy)
o HBO can increase cytotoxicity of cis-platinum
- Uncontrolled high blood pressure
o HBO can increase systemic vascular resistance
- Unstable angina or myocardial infarction within the previous 3 months
o Increased afterload due to HBO can increase myocardial workload
- Cardiac EF ≤ 35%
- Pulmonary edema can arise with HBO in certain patients with severe heart failure
- In patients with prior history of CHF, subsequent echocardiogram and ECG are
required to establish EF>35%
- Treatment with disulfiram
o Disulfiram inhibits superoxide dismutase and is not approved for use concomitantly
with hyperbaric oxygen therapy
- Active drug/alcohol dependence or abuse
- Lack of adequate social support structures, e.g. homelessness
- Tumors with potential confounding results on serum marker studies
- Small cell (neuroendocrine) carcinomas
- Carcinoid tumors