What is Hyperbaric Treatment of Brain Radiation Necrosis?
Brain soft-tissue radionecrosis typically happens in the part of the brain that was exposed to radiation during cancer treatment. Here, radionecrosis means the death of brain tissue. This condition can start as early as six months post-radiation therapy. Although it’s a delayed effect of the treatment and can happen several years later, it usually occurs within the first one or two years after the treatment.
What Causes Hyperbaric Treatment of Brain Radiation Necrosis?
The chance that someone will experience negative long-term effects from radiation therapy, including brain tissue damage or necrosis, is impacted by multiple factors. These include the dosage of radiation received, the form of radiation used, the specific brain area and amount of brain tissue exposed to radiation, the person’s genetic factors, and any usage of chemotherapy or medication to enhance the effects of the radiation.
Radiation necrosis, or damage from radiation exposure, typically occurs in the same area where the original brain tumor was located. But it could also affect any areas of the brain that were within the range of the radiation treatment. Giving radiation to the whole brain puts the patient at a higher risk compared with just treating a small section of the brain.
Most people who receive radiation therapy don’t develop radiation necrosis. Nonetheless, a noticeable amount of patients might encounter this severe side-effect. Different studies show a range of potential risk, with as few as 5% and as many as about 37% of patients potentially developing this issue after radiation therapy.
Risk Factors and Frequency for Hyperbaric Treatment of Brain Radiation Necrosis
The occurrence of radiation necrosis of the brain, which is a side effect of treating the brain with radiation, happens in about 2.5 to 24% of patients who receive this treatment.
Signs and Symptoms of Hyperbaric Treatment of Brain Radiation Necrosis
Radiation necrosis is a condition that can cause a variety of symptoms depending on which part of the brain is affected. Common symptoms include headaches, sleepiness, memory loss (particularly if the memory-controlling part of the brain, the temporal lobe, is involved), changes in personality, and seizures. Radiation therapy on the whole brain, a common treatment for lymphoma, can result in a widespread disease of the brain.
- Headaches
- Sleepiness
- Memory loss (if the temporal lobe is affected)
- Changes in personality
- Seizures
- Widespread disease of the brain (if the whole brain is affected)
Testing for Hyperbaric Treatment of Brain Radiation Necrosis
One of the challenging parts of diagnosing radiation damage to the brain, or “radiation necrosis,” is that it can look similar to a recurring tumor. This is particularly true for a type of brain cancer called glioblastoma multiforme, which might have a specific pattern of tissue death that can be confused with radiation necrosis.
Brain MRI scans that measure blood flow can aid in the diagnosis. In cases of radiation damage, there’s usually a lack of a marker called T2 flair. This marker, which commonly appears in the brain’s white matter in cases of tumors, is typically absent in radiation necrosis.
A type of MRI technique, called MR spectroscopy, usually shows low levels of substances called choline, creatine, and NAA in cases of radiation necrosis. Another kind of scan, called a FDG-PET scan, typically shows lower activity in areas of radiation necrosis. In contrast, recurring tumors usually show increased metabolic activity, meaning they use more energy.
However, conventional imaging methods can sometimes be deceptive. In some cases, a surgical biopsy might be necessary to determine conclusively whether a lesion, or abnormal tissue, is due to radiation damage or the return of cancer.
Treatment Options for Hyperbaric Treatment of Brain Radiation Necrosis
When treating patients with radiation necrosis, doctors generally group patients into two categories: those who do not show symptoms and those who do.
For patients who don’t show symptoms, serial MRI scans can be performed to track the suspected affected area over time to see if it changes, or to consider the possibility of the return of a tumor. If the affected area keeps growing, a biopsy, or a procedure to extract a small sample from the body for closer examination, might be necessary to determine if it’s radiation necrosis or a recurring tumor. It’s very critical to confirm this diagnosis to ensure the patient gets the right treatment.
If the patient is experiencing neurological symptoms or increased pressure in their skull, then surgical interventions, steroids, anticoagulation therapy (a method to prevent blood from clotting), or even hyperbaric oxygen therapy might be considered. Hyperbaric oxygen therapy is a treatment where the patient breathes 100% oxygen in a pressurized chamber. A newer treatment using a medication called bevacizumab has shown some promise for treating radiation necrosis but is not yet considered the standard treatment.
Hyperbaric oxygen therapy has demonstrated potential benefits in case studies and prospective studies, although there’s no definitive evidence. This treatment can enhance healing by improving the formation of new blood vessels, which then results in better blood flow to the tissues. It may reduce swelling in tissues and stimulate collagen production, a protein that is vital for healing damaged tissue.
Radiation necrosis is partly caused by a process that leads to cell death, primarily through deprivation of blood supply, a phenomenon known as ischemia-reperfusion injury. Hyperbaric oxygen therapy can help heal the damaged tissue by restoring normal cellular functions.
Usually, hyperbaric oxygen therapy is delivered at a specific pressure level for a duration of 90 to 120 minutes every day. It may take anywhere between 20 to 30 treatments for significant new blood vessel formation to occur, which can lead to the improvement of neurological symptoms.
The major downsides of this therapy are that it’s expensive, time-consuming, and not widely available, although more and more facilities offering this therapy are being built.
More research is needed to understand the best treatment practices with hyperbaric oxygen therapy alone and in combination with other treatments like steroids and surgery. It would also be interesting to examine the combined effects of bevacizumab, which inhibits a certain growth factor, and hyperbaric oxygen therapy, which enhances it. Such studies might reveal more about how hyperbaric oxygen therapy works.
What else can Hyperbaric Treatment of Brain Radiation Necrosis be?
The key challenge in diagnosing radiation necrosis is that it can often be confused with the regrowth of the tumor. The difference between the two conditions can usually be identified through certain imaging results, which are elaborated under the section “Evaluation”.
What to expect with Hyperbaric Treatment of Brain Radiation Necrosis
Looking back at previous studies, it has been shown that with treatment, about 70-80% of patients have seen stability or improvement in their conditions. These results hold a lot of promise, but please remember they come from smaller studies and may not reflect everyone’s experience.
Possible Complications When Diagnosed with Hyperbaric Treatment of Brain Radiation Necrosis
Barotrauma of the ear, difficulty in breathing or shortness of breath and collapsed lung (pneumothorax), and chest tightness because of excess oxygen in the body are medical conditions that may occur.
Common Medical Conditions:
- Barotrauma of the ear
- Difficulty in breathing or pneumothorax
- Chest tightness caused by oxygen toxicity
Preventing Hyperbaric Treatment of Brain Radiation Necrosis
The patient should understand details about their treatment, possible complications that may arise, and the fact that they will need to stay inside the treatment chamber until their therapy session is completed.