A Proof-of-principle Study of Hyperbaric Oxygen as a Radiosensitizer Prior to Stereotactic Radiosurgery for Brain Metastases
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Patients with brain metastases who are candidates for treatment with stereotactic radiosurgery (SRS) are potential study participants. SRS delivers high-energy, precisely-focused radiation to each brain metastasis to shrink the tumor, and is the standard-of-care for patients with these tumors. Oxygen enhances the damaging effects of radiation on tumor cells. Hyperbaric oxygen (HBO) therapy increases oxygen levels in all kinds of tissues, including tumors. The purpose of this trial is to study whether it is feasible to treat patients with HBO just prior to receiving SRS, given the timing constraints of treating sequentially with HBO and then SRS. Patients will undergo HBO treatment followed by the placement of a Gill-Thomas-Cosman head frame then transported ,via stretcher, to receive SRS. The transfer and placement of the head frame needs to be completed within the 15minute time frame. The trial's secondary objectives are to determine whether it has any effects on outcomes and quality of life. As part of study participation patients will be asked to complete quality of life questionnaires as well as mini mental status questionnaires. These will be done prior to treatment and at follow up appointments throughout the next 3 years while participating in the study. Patients will be given the option to participate in the optional bio marker blood draw study which would require patients to have blood drawn at three time points, pre-treatment, the day after treatment and at their first follow up visit.
Condition or disease
Other: Hyperbaric oxygen given at 2.4 ATA for 30 minutes immediately prior to SRS - HBOT for 30 minutes - SRS without prior HBO
Statistical Methods for the primary outcome variable of feasibility [ Time Frame: Time line for completion of the study is 3 years. ]
For the primary outcome variable of feasibility,the 20 evaluable patients will be analyzed on the basis of the amount of time required from leaving the HBO chamber to beginning the SRS for the target lesion(T1).The goal for each patient is for T1 to be no greater than 15 minutes.We anticipate a learning curve for the team members of this study.
The primary endpoint of feasibility is defined as having been achieved if more than 50% of the 20 evaluable patients start SRS treatment within 30 minutes of leaving the HBO tank:in other words,T1 is <=30minutes >50% of evaluable patients.
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Ages Eligible for Study:
18 Years to 80 Years (Adult, Senior)
Sexes Eligible for Study:
Accepts Healthy Volunteers:
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
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