I know too well the dilemmas facing Ashya King's parents

http://www.theguardian.com/commentisfree/2014/sep/06/ashya-king-brain-tumour-my-son-same-cancer-treatment

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In 2010, my son was diagnosed with a medulloblastoma, the same childhood brain tumour for which Ashya King's parents are now seeking proton beam therapy in the Czech Republic.

He was diagnosed a few months before his 6th birthday. For the next 18 months, I did not leave his side. We quickly developed our own private language – talking in physically close whispers to carve out our world from the rooms full of (often strange) people.

We spelled messages to each other across crowded waiting rooms using the sign language alphabet we were sure no one else could decipher, exchanging meaning-filled but wordless looks, a rich, virtual vocabulary that seemed to have sprung up suddenly and fully formed. I was determined to be the thing he could take for granted when everything else was being pulled apart.

This is what makes the four-day separation of Ashya King from his parents almost unbearable to contemplate. I have been trying to describe the feeling, but the words disintegrate between my fingers in a pile of dust. So I am, in a very personal way, relieved that Ashya and his parents have been reunited.

But this episode has stirred (other) sleeping demons. Childhood brain tumours are typically treated with a combination of chemotherapy drugs and radiotherapy (high-energy x-ray radiation). Radiotherapy is particularly effective for treating medulloblastoma, the specific tumour that Ashya has and our son had.

During our first two-hour meeting with his oncologist, I took seven pages of notes about the NHS's medulloblastoma medical protocol (treatment plan), the very one Ashya's parents are now challenging. Four of those pages were all about the treatment's inevitable toxic effects – on his brain function, on his fertility and growth, on his hearing… the price of survival.

Medicine is not an exact science and the medical protocols can feel arbitrary, particularly if you look behind them and into the dark universe of the medical research underpinning them. Those who do look might find something that looks like hope, in a recent academic article in a specialist medical journal or on an online community bulletin board.

Frankly, when your child has been diagnosed with a potentially life-threatening illness, your critical faculties might relax a fair bit. You might contemplate things you'd have previously discarded as fanciful or simply "as yet unproved". Some will seem bonkers (coffee enemas, for instance), while others will just be very "new" (proton beam therapy, for instance).

As your child's chief medical advocate, you will want to turn every stone to maximise success and minimise harm. The doctors might find it exasperating at times, but will, it's hoped, understand you are just doing your job, much as they are doing theirs.

In some cases, pushing them will actually make a difference to the treatment chosen (it did in ours), and doctors are often receptive to, even grateful for, this greater parental engagement in the child's treatment.

Of course their answer might still be "no" ("not available" or "not appropriate in this case"). At this point, some parents and patients might yearn for the medical innovation of the US, where doctors can develop their own treatment protocols and compete for patients in a (private) medical marketplace. There, it is said, if you can pay for it, you can have it. The NHS, on the other hand, is a state-run, publicly funded bureaucracy.

Because the NHS is publicly accountable, it takes fewer risks and will adopt a new protocol only after it has been satisfied by a longer tail of evidence of its clinical (and cost) effectiveness. Sometimes, it will adopt a new treatment protocol, but will be unable to deliver the treatment itself – this is the case with proton beam therapy. University College London hospital foundation trust and the Christie Hospital foundation trust in Manchester are currently developing proton beam therapy centres; in the meantime, the NHS funds qualifying patients to go abroad for treatment. Appetites for medical risk-taking will vary and the best place to get sick is somewhere in the theoretical mid-Atlantic.

But, whatever might have gone wrong in Southampton, I am glad we were here, in the care of the NHS. No one had prepared us for the expectation-busting, linked-up care we received through the seamless partnership of doctors and nurses at Great Ormond Street hospital, University College hospital, our local hospital and our local community nursing team. This team included oncologists, radiotherapists, psychotherapists, endocrinologists, audiology and ENT specialists and ophthalmologists. The system worked and the dropped jaws of friends in other countries are still scraping the floor. And crucially, our son is doing very well.

But now, four years later, Ashya's case has reignited the arguments in favour of proton beam therapy, primarily its claims to spare healthy tissue, unlike the more common x-ray based radiotherapy our son received. This means proton beam patients might need less (or no) hormone treatment to compensate for the unintended fall-out of the radiation on their pituitary and thyroid glands. Their memory, concentration and ability to process information might not be (as) compromised and their risk of cataracts or secondary cancers later in life might not be increased by x-ray exit doses.

So now I'm obsessing over whether we did the right thing four years ago. When doctors told us proton beam therapy was "not appropriate in this case", should we have pushed harder? What do we actually know now that we didn't (and, crucially, that we couldn't) know then? I had built myself a firmament of confidence about our thoroughness and our choices. Now it's being infiltrated by doubt and I'm stressed.

All being well, this firmament will never be safe from attack. It might seem perverse but part of me hopes it continues to be hit by more doubts of this kind, more often, more intensely, starting as soon as possible. I want medical research to continue to develop more effective treatments, less toxic treatments, quicker and less painful treatments, cheaper and more accessible treatments. Every time it does, I will kick myself and my emotional roof will leak, but it will be worth it.

Camilla Bustani lives in London with her husband and two children. This month is CLIC Sargent's childhood cancer awareness month (clicsargent.org.uk/content/childhood-cancer-awareness-month)