Hyperbaric oxygen (HBO) therapy
This information is about the use of hyperbaric oxygen therapy (HBO) for people with cancer. HBO therapy is sometimes used to treat a number of severe side effects of treatment for cancer.
- HBO therapy
- What HBO therapy is used for
- How it works
- HBO therapy use in cancer
- When HBO therapy is used
- How HBO is given
- Possible side effects
- Less common side effects
HBO therapy
Hyperbaric oxygen therapy is a form of treatment which involves providing the body with extra oxygen. 'Hyper' means increased and 'baric' relates to pressure. Oxygen (O2) is one of the gases in the air that we breathe, and is essential for life. The air that we breathe normally contains 21% oxygen.
In HBO therapy, more oxygen is forced (pressurised) into normal air. (This can only be carried out in special chambers called hyperbaric oxygen chambers). People can breathe this increased oxygen by sitting in the chamber and using a mask or a hood.
Hyperbaric oxygen chambers were originally designed to treat deep sea divers for decompression illness (the 'bends'), and to treat severe carbon monoxide poisoning.
What HBO therapy is used for
HBO therapy can help in a number of different situations where body tissues have suffered from a decrease in oxygen levels. These include:
- decompression illness (divers who suffer from the bends)
- severe carbon monoxide poisoning
- smoke inhalation
- chronic wounds and some infections
- wound healing after reconstructive surgery
- radiation necrosis (body tissue dying off after radiotherapy treatment)
- acute blood loss where a blood transfusion is not possible (for Jehovah's Witnesses)
How it works
Oxygen is carried around the body by the blood. Breathing in 100% (pure) oxygen, under increased pressure (HBO), allows extra oxygen to be forced into the blood stream and dissolved at a far greater rate than if pressure was not used. This extra oxygen can help where healing is slowed down by infection or limited blood supply due to damage to the tissues. HBO therapy:
- encourages new blood vessels to grow and carry additional blood
- increases the ability of the body's defence mechanisms to fight infection and kill bacteria
- helps reduce any swelling that may occur around the area
HBO therapy use in cancer
Radiotherapy treatment for cancer can cause changes in the oxygen supply to tissues in the treated area. This is because radiotherapy affects normal cells and blood vessels as well cancer cells.
The small blood vessels in the treated area can be damaged by radiotherapy treatment, causing less blood to be supplied to that area. When this happens, it becomes more difficult for essential oxygen and nutrients to reach the tissues. Over a period of time, these affected tissues may deteriorate and become fragile. The tissues may break down and form areas of ulceration and, although not common, some tissues may eventually die off completely (radiation necrosis). These radiation injuries can occur very slowly over a number of months or even years.
Although HBO treatment has been available for a long time, its use for these effects of cancer is relatively new. More research into the use of HBO in treating the long-term side effects of radiotherapy is needed before it becomes more widely used in the UK. However, previous studies have suggested that HBO may be effective in the following conditions.
Chronic lymphoedema in breast cancer
Radiotherapy is often given after breast conserving surgery for breast cancer. A potential side effect of radiotherapy to the breast and armpit is lymphoedema (especially if all the lymph nodes have been surgically removed).
Lymphoedema is a swelling in the arm because of an abnormal collection of lymph in the body’s tissues. It can also cause pain and redness (erythema). It is thought that HBO therapy may help these symptoms by reducing the swelling in the area. Research trials are looking at how effective HBO therapy is in treating lymphoedema.
Chronic radiation cystitis
Radiotherapy is used as a treatment for some types of pelvic cancer. Sometimes treatment can lead to chronic cystitis (inflammation of the bladder tissues). Symptoms include urinary frequency (needing to go a lot), pain when passing urine, and blood in the urine (haematuria). These problems can occur months or years after treatment. Symptoms can be persistent and range from moderate to severe. HBO therapy may be used to help relieve things when other forms of treatment have been tried without success.
Osteoradionecrosis
Radiotherapy is often used for cancers in the head and neck. The tissues around this area are fragile and may break down after radiotherapy, particularly if previous surgery has been carried out. Although it is rare, the bone itself can be affected by radiotherapy and start to break down and die. This is known as osteoradionecrosis. It can also happen when radiotherapy is given to other areas of the body, such as the chest or the pelvis.
Treatment for osteoradionecrosis includes antibiotics, ‘washing-out’ the area with salty water (saline irrigation), and sometimes surgery to remove some or all of the affected bone. Although HBO therapy cannot restore the dead bone, increased oxygen can help the tissues around the area to heal by encouraging blood vessels to grow. HBO therapy can also be given before reconstructive surgery to help the healing process and prevent infection. If wounds or tissue are infected, treatment would usually consist of medicines or surgery as well as HBO therapy.
Tooth removal
Having a tooth removed shortly before, during or after radiotherapy treatment to the mouth and jaw area may increase the risk of osteoradionecrosis. This is because of the reduced oxygen supply to the area. HBO therapy can be given as a preventative measure, if used both before and after the tooth extraction, to stimulate the healing process.
Chronic radiation proctitis
Radiotherapy can be given for pelvic and bowel cancer. The rectum is very sensitive and although rare, long-term symptoms due to radiation damage can occur. These include pain, bleeding and irregularity in bowel habits. If these symptoms do not improve following treatments such as anti-inflammatory medicines, HBO therapy may be helpful.
When HBO therapy is used
Your doctor can refer you for HBO therapy if you have long-term side effects of radiotherapy that have not responded to normal treatment. Your consultant can advise you whether HBO therapy is appropriate in your situation.
HBO therapy is not always offered as a routine treatment for radiation damage, as it is a fairly new treatment in cancer care and knowledge about the potential benefits is not widespread. You can be referred for treatment by your GP or hospital specialist. Treatment is only offered at specialised centres throughout the UK, so you may have to travel some distance.
Before having HBO therapy you will be examined by a doctor to make sure that you are fit to receive this type of treatment. HBO therapy is not suitable for all people, and is not advised if you are pregnant, suffer from fits, or have severe chest disease or problems affecting your ears or sinuses. Treatment is not recommended if you have a fear of enclosed spaces (claustrophobia).
If you smoke, you may be asked to stop smoking before and during treatment as this is likely to affect the oxygen levels.
How HBO is given
Treatment is usually painless and is carried out in specially-designed chambers. There are two types of chamber: a monoplace chamber and a multiplace chamber.
A monoplace chamber is designed to treat one person at a time and involves lying on a 7ft padded stretcher that slides into a clear plastic tube (chamber) about 2ft wide. Once you are inside, the door is closed and the chamber is pressurised. You will be able to see and talk to a member of staff at all times during the treatment.
Multiplace chambers are designed to hold and treat several people (up to 12) at a time, and are more commonly used. These chambers are quite large and you will be able to walk about inside. Once you are sitting or lying inside the chamber, the doors will be closed and air is blown into the chamber to increase the pressure. You will hear a sound similar to that in an aircraft as the air begins to circulate. You will start to feel a sensation of fullness in your ears and will be shown how to ‘clear’ your ears. It is important to do this in order to equalise the pressure in the ears and to help prevent any pain in your ear drum.
When the pressure reaches the correct level, staff in the chamber will help you to put on either a mask or a clear hood to receive 100% oxygen. Trained staff usually stay with you throughout the treatment session and you can talk to staff outside as well should you need anything. You should be able to relax, read, or listen to music.
Near the end of the treatment the pressure in the chamber is gradually decreased over a period of time. You may feel popping in your ears during this time. After the decompression phase you can leave the chamber.
The length of each treatment varies depending on what you are being treated for and can last anywhere from 60–150 minutes at a time. Treatments are usually repeated over a number of days, or several weeks. For maximum benefit the entire course should be completed.
Treatment sessions are likely to be postponed if you are suffering from colds or flu, runny nose, cold-sores, nausea, vomiting or are generally feeling unwell. You should let your nurse or doctor know if you have any of these symptoms before starting a treatment session.
Possible side effects
HBO therapy is a relatively safe treatment with few serious side effects. Any side effects are usually minor and short lived. We have outlined the most common and less common side effects so that you can be aware of them. If you notice any other problems which you think may be due to the treatment, please discuss them with your nurse or doctor.
Blurred vision can occur after having multiple treatments and is due to the development of short sightedness (myopia). The effect usually comes on gradually and then gets better slowly when treatment ends. Temporary use of glasses or a change in prescription may be helpful, but the blurred vision only lasts a few weeks at most.
Light-headedness Some people feel light-headed after treatment. This only lasts for a few minutes.
Fatigue Tiredness is a side effect which can be more of a problem if you have treatment more than once a day. The effect usually wears off after a few days once the treatment sessions are finished.
Less common side effects
Ear problems Although rare, damage to the middle ear can occur due to the change of pressure. This can cause pain in the ears and bleeding if a rupture occurs. You will be shown how to equalise the pressure in your ear during treatment, which can help to prevent any ear problems.
Sinuses The change in pressure may cause congestion of sinuses, leading to headaches or facial pain. Usually this can be controlled with decongestant medicine but occasionally HBO therapy needs to be stopped.
