Sep 05 2014

Ashya King and Proton Beam Therapy

These cases are always heart-breaking and difficult to write about, but many people have been asking me about the Ashya King case and there are are few points worth exploring.

For background, Ashya King is a 5-year old boy living with his parents in the UK. He has a type of primary brain tumor called a medulloblastoma. This is the most common type of malignant brain tumor in children, and typically is located in the back of the brain, in what is called the posterior fossa.

His parents, who are understandably concerned and want the best treatment for their son, would like him to receive a new type of therapy called proton beam therapy. His UK doctors do not feel this specific treatment is indicated. In desperation, Ashya’s parents removed him from his UK hospital and drove him to their vacation home in Spain. Their plan was to obtain proton beam therapy in Spain.

In reaction police in the UK issued an interpol missing persons alert for Ashya and an arrest warrant for his parents, claiming that this was a kidnapping. They have since been arrested and are currently in jail. This, of course, has sparked the current controversy.

It does seem that everyone is calming down a bit. The arrest warrant has been removed and hopefully Ashya’s parents and doctors can work this out. It is likely that everyone just wants what is best for Ashya, and now that the world is paying attention he will likely get it.

Proton Beam Therapy

At the center of this incident is a very interesting technological development in the treatment of certain cancers. Cancer treatment is largely based on killing or removing cancer cells while minimizing damage to healthy tissue. Cancer cells are very rapidly dividing, which is one feature that can be targeted by treatment.

Radiation kills living cells, mainly by destroying its DNA. Early radiation therapy for cancer simply exposed the part of the body with cancer to high energy photons. Surrounding tissue was also harmed, and the total dose was limited to minimize tissue damage, but significant damage to surrounding tissue was unavoidable.

This technique was later refined so that beams of various intensities are given from specific directions and through portals that shape the radiation exposure to the tumor. Multiple directions are used, all overlapping on the tumor, to further minimize exposure to healthy tissue.

Stereotactic beam therapy further refines this method, shooting photons from many directions guided by 3D imaging to precisely target the tumor.

Proton beam therapy is now the next step in this process. Like photon therapy, a beam of protons can be aimed from multiple direction to precisely conform to the 3-dimensional shape of the tumor. The proton beam has an added advantage, however – protons have a more limited penetration through tissue. Further, they deposit most of their energy close to the limit of their penetration, at what’s called the Bragg Peak. There is limited exit radiation.

What this means is that oncologists can use proton beam therapy to deliver a lethal dose of radiation to a tumor, while sparing adjacent tissue. This is especially useful in children, and or tumors that are deep or next to vital structures.

Proton beam therapy is currently in the process of being studies and adopted. It takes time for centers to acquire the equipment and develop a program with the necessary expertise to use a new technology such as this. It’s therefore not instantly available everywhere.

Further, a new technique such as this has to be studied with every type, location, and stage of cancer to see if it is effective and if it provides any actual advantages in outcome.

The evidence so far strongly suggests that proton beam therapy does have superior outcomes with treating medulloblastoma in children. A recent study found:

Passively scattered proton CSI provides superior predicted outcomes by conferring lower predicted risks of second cancer and cardiac mortality than field-in-field photon CSI for all medulloblastomapatients in a large clinically representative sample in the United States, but the magnitude of superiority depends strongly on the patients’ anatomical development status.

That sounds promising. Keep in mind, however, that treatment recommendations always depend on the particular details of an individual case. That is why I am not offering an opinion as to whether this therapy is appropriate for Ashya specifically – only his oncologists or an expert with complete access to his medical records will have sufficient information to make such a judgement.

Parental Rights vs Medical Responsibility

At issue here is the occasional conflict between parental rights and the responsibility of health care providers, and the state, to care for minor children. This topic usually comes up in the context of parents who wish to deprive their children of standard of care treatment, either due to religious beliefs or because they prefer some alternative treatment instead.

In cases where parents wish, for whatever reason, to deprive their children of standard of care medicine, I personally think the issue is fairly clear – parents do not have the right to sacrifice their own children at the altar of their religious beliefs, philosophy, ideology, or scientific illiteracy. In such cases the state has a right to step in and defend the rights of children to basic medical care.

Ashya King, however, is not such a case. In this situation the parents want a new and potentially superior therapy. I don’t know exactly why his doctors do not feel proton beam therapy is indicated. The possibilities include: 1) They consider the treatment to still be experimental. 2) The anatomical or other details of Ashya’s tumor do not lend themselves to this therapy, or proton beam therapy would not be superior to more traditional photon therapy. 3) The UK health system has simply not caught up bureaucratically to this new development and they are being somewhat inflexible in the application of their current rules.

I suspect the doctors feel the answer is some combination and 1 and 2, while the parents worry the real answer is the third option. I don’t have enough information to know, and so I am reserving judgement.

Conclusion

The case of Ashya King is interesting, and I will certainly follow the case to see how it develops. I am particularly interested in any further information to explain the position of Ashya’s UK doctors. As I wrote above, I think it’s best to reserve judgement in these cases until sufficient information is available. It’s tempting to moralize over such cases, but doing so prematurely is not fair or helpful.

Of course, no matter how it happens, I wish the best for Ashya King. I can’t imagine what his parents are going through and I can understand their desperation.

It certainly would be a good thing if Ashya were reunited with his parents during this difficult time, and if everyone involved can rationally decide on what treatment is best for Ashya, without getting Interpol or the international media involved.

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