Clival chordoma research
Home › Diet, supplements and claims

Hydrogen before radiotherapy, hyperbaric oxygen after

Written 13 September 2026 for her partner, after he asked whether it would be reasonable to use hydrogen up until two weeks before proton beam therapy and then hyperbaric oxygen afterwards to help with healing.

Short version. The shape of the plan is right and the instinct behind it is good. There are two things to change: hydrogen has to be off for the whole course of radiotherapy and not just the fortnight before it, and hyperbaric oxygen is a weaker idea than it looks, for reasons that are specific to the patient.

Nothing here is a reason not to do anything. It is a reason to do it in the right order, and to ask two questions of the team before booking anything.

1. Stopping the hydrogen before radiotherapy: right, and for a better reason than you think

Radiotherapy works largely by splitting water inside the cell. The pieces it makes, free radicals, are what damage the tumour's DNA. The main one is called the hydroxyl radical.

Hydrogen's entire selling point is that it mops up hydroxyl radicals.

So taking hydrogen through radiotherapy is not a neutral act. In principle it could protect the tumour from the treatment she is having the treatment for. This is the same objection that applies to high dose vitamin C, and it is in the Dalgleish note already.

One point in your favour. Protons are not photons. They dump most of their energy in a short dense burst at the end of their travel, and that kind of damage is more often a direct hit on the DNA and less often radical driven. So the concern is genuinely smaller with protons than it would be with ordinary radiotherapy. Smaller, not gone, and nobody has measured it in a person.

The evidence that decides it is not about hydrogen at all. There is one large randomised trial of giving an antioxidant through radiotherapy. Bairati and colleagues gave 540 head and neck cancer patients vitamin E, 400 IU a day, or a dummy, starting on the first day of radiotherapy. The vitamin E group had fewer acute side effects from the radiotherapy. They also had nearly three times the rate of new cancers during the period they were taking it, and a higher rate of recurrence. When the supplement stopped, the effect reversed.

That is the trade in one study: the supplement made the treatment more comfortable and made the cancer outcomes worse while it was being taken. Hydrogen is a different molecule and the trial does not transfer directly. But it is the only proper human test of the general idea, and it went the wrong way.

The one hydrogen trial that bears on this is Kang 2011: 49 people having radiotherapy for liver tumours, hydrogen water or placebo, quality of life better, and no difference in how the tumours responded. That is reassuring as far as it goes. It is one small trial in a different tumour with a different beam.

2. The change to make to the plan

Proton therapy for a clival chordoma is usually about seven to eight weeks of treatment, five days a week.

Your plan as written stops hydrogen two weeks before it starts, which means she would be taking it right through the course itself. That is the window that matters most.

So: hydrogen up to two weeks before the first session, then nothing at all until the last session is done.

Keep the two weeks. It is more than the chemistry needs, and it costs nothing. Hydrogen gas itself is gone within hours, she breathes it out. The reason for the longer gap is that hydrogen also switches on the cell's own antioxidant machinery, and that takes days to a week to settle back down.

The same rule should apply to any other antioxidant she is taking, including vitamin C. Vitamin D is different and is not affected by this: it is a hormone being topped up to a normal level, not an antioxidant.

3. Hyperbaric oxygen afterwards: the honest picture

This is the part of the plan with the most published evidence behind it, and it is still not what you are hoping for.

The Cochrane review was updated in 2023. Eighteen trials, 1,071 patients. What it found:

That last line is the one that matters for the patient. What the beam will pass through in her case is skull base bone, the nerves to her eyes, the trigeminal nerve and the front of the brainstem. Hyperbaric oxygen has a case for the bone. For the nerves, which are what her symptoms are actually made of, it has not been shown to do anything.

And it is a treatment for damage that has already happened, usually months or years later. It is not a recovery programme you run after radiotherapy because it seems sensible.

The trial that tested exactly that idea was British and it was negative. HOPON gave hyperbaric oxygen to prevent jaw bone necrosis after dental surgery in irradiated patients. The rate was 6.4 percent with it and 5.7 percent without. No difference.

On the worry that oxygen feeds cancer: the honest answer is reassuring. The old fear has been looked at and has not held up. There is no chordoma data at all, but there is no signal anywhere that hyperbaric oxygen drives recurrence.

4. The part that is specific to the patient, and the reason to ask before booking

Hyperbaric oxygen means being taken to two or two and a half times normal atmospheric pressure. Every air space in the head has to be able to equalise. The commonest complication in ordinary people is damage to the ears and sinuses from pressure.

The patient is not an ordinary patient for this:

An unrepaired skull base defect, a fluid leak and air trapped inside the head are all treated as reasons not to give hyperbaric oxygen. Air can be forced into the head and cannot get back out. There are published cases of this happening after a single session.

Separately, she has had four brief episodes since 5 September that may be small seizures. Oxygen at pressure makes seizures marginally more likely.

None of this means never. It means the decision belongs to her skull base surgeon and a hyperbaric doctor together, after someone has looked at the repair, and not to a private clinic that will take the booking.

4b. The window between surgery and radiotherapy, added 18 September 2026

Her partner asked about the specific idea of using hyperbaric oxygen in the gap between resection and proton therapy, to let traumatised tissue heal and toughen up before the beam. It is a more sensible sounding claim than the general one and it deserves a straight answer, which is that it is the worst version of the idea for the patient rather than the best.

The concept has been tested in its strongest setting and failed. Giving hyperbaric oxygen to tissue in advance so that it withstands radiation better is prophylactic use, and that is exactly what HOPON tested. It made no difference: 6.4 per cent against 5.7 per cent. When an idea has been tried where it should work best and did not, that is the answer until someone produces a trial showing otherwise.

For her, that window is the contraindication window, not the opportunity window. If she has an endonasal resection she will have a fresh skull base repair, very often a nasoseptal flap, frequently some air inside the head afterwards, and a period where a spinal fluid leak is the thing everyone is watching for. Air trapped in the head, an unrepaired defect and an active leak are the standard reasons to refuse hyperbaric oxygen. The first weeks after that operation are precisely when all three are most likely to be present. The safest moment for hyperbaric oxygen is long after the repair has been confirmed healed, which is not the window in question.

The bigger risk is the clock. A hyperbaric course is typically twenty to forty daily sessions over four to eight weeks. The standard plan after resection of a chordoma is to start radiotherapy as soon as the wound allows, usually around four to six weeks, because residual disease is left behind in almost every case and it starts growing again immediately. The observational evidence points the same way: longer intervals to radiotherapy go with worse local control. So a course of hyperbaric oxygen in that window does not simply add an unproven treatment, it competes for the weeks that matter most, against a tumour where local control is close to everything.

Where it is genuinely used after surgery, and where her team might legitimately offer it, is rescue rather than routine: a flap or graft that is actually failing. That is an accepted indication. It is not the same as giving it to a flap that is healing normally.

What does help tissue in that window, and is worth putting the effort into instead: protein and calories at target, vitamin D repleted to a normal range rather than a megadose, good glycaemic control, no smoking, and the question of whether her anti-inflammatory should pause around the operation, since NSAIDs and bone healing is a real consideration at the skull base and one for the surgeon rather than for us. And not letting anything push the proton start date.

5. The plan I would write instead

6. Three questions for Mr Syrris on Wednesday

  1. Does she need to stop antioxidant supplements during proton therapy, and which ones? Who gives us that list, you or the proton centre?
  2. If she has surgery through the nose, would the skull base repair ever rule out hyperbaric oxygen, and for how long?
  3. Who decides about hyperbaric oxygen afterwards, the proton centre or Southampton?

Where the numbers come from

Full working, with the evidence levels and the parts I am less sure about, is in research thread 22.

Brief for the family · source file em-docs/em-hydrogen-hbot.md · last edited 18 September 2026