Is spending on proton beam therapy for cancer going too far, too fast?BMJ 2012; 344 doi: http://dx.doi.org/10.1136/bmj.e2488 (Published 17 April 2012) Cite this as: BMJ 2012;344:e2488
You might think that this week’s study of 12 000 patient records showing that men with prostate cancer treated with expensive proton beam therapy had more complications than patients given conventional radiotherapy would dent some people’s faith in the newer treatment.1 No clear evidence of better effectiveness exists, and it now appears that the treatment may have a downside.
But the spread of proton beam therapy for cancer has such momentum it now seems unstoppable. Millions of dollars have been invested in building the particle accelerators necessary to deliver it.
Globally, 39 facilities are in use. The US has 10 proton beam centres, and 19 more are being built. More than $370m (£230m; €277m) are being spent on a project to bring accelerators to centres in Minnesota and Arizona. And the UK’s health secretary Andrew Lansley announced in December that £150m would be put into delivering such treatment in the NHS.2
Some people have recognised the rashness of the dash to introduce these machines, which have been described as the world’s “most costly and complicated medical devices.”
Proton beam therapy was described earlier this year as “crazy medicine and unsustainable public policy,” by Ezekiel Emanuel, a professor at the University of Pennsylvania, oncologist, and former adviser to President Obama. “If the United States is ever going to control its healthcare costs, we have to demand better evidence of effectiveness and stop handing out taxpayer dollars with no questions asked.”
The cost of proton therapy for prostate cancer is typically about twice as much as conventional radiation, three times as much as surgery, and four or five times as much as brachytherapy.
So what is the evidence for and against the treatment? The theory is that proton beams target cancerous tissue more exactly. By accelerating subatomic particles towards the speed of light and concentrating them in a beam, proton treatment is thought to target cancerous tissue more precisely, minimising harm to healthy tissue while reducing side effects and increasing cure rates.
It has been shown to be beneficial and cost effective for treating children, whose tissue can be highly sensitive to stray radiation, and for certain uncommon brain cancers.
But proton accelerators, especially in the US, are being marketed as treatment for prostate cancer rather than just childhood cancers, partly because the greater numbers of patients makes the financial returns better.
Not only is the benefit unclear in prostate cancer, but the side effects appear, in some cases, to be no better than for conventional radiotherapy, which undermines one of proton therapy’s selling points. In June 2011, a study of radiation therapy for prostate cancer found that patients receiving conventional radiation experienced fewer gastrointestinal problems than a similar group exposed to proton beams.5
“Somewhat surprisingly, proton therapy had the highest GI toxicity of the radiation modalities,” the authors noted.
Signs that proton beam therapy is less cost effective than conventional radiation for prostate cancer have been increasingly evident since 2007. In a study funded by the National Institutes of Health researchers calculated mean costs of around $64 000 for men in their 60s and 70s—significantly higher than the $39 000 for intensity modulated radiation therapy.6
“New treatments are introduced routinely into clinical practice without rigorous economic analysis,” noted the study’s authors. They urged “limiting the number of proton facilities” before more comprehensive analyses are done.
Despite the huge amount of money sunk into building accelerators, the first randomised controlled trial comparing x rays with proton beams is only just about to begin. That research, involving 400 patients and sponsored by the US National Cancer Institute at Massachusetts General in Boston and the University of Pennsylvania in Philadelphia, won’t be completed for seven years.
Harvard Medical School radiation oncologist Anthony Zietmen told the BMJ: “We rush into treatments before they are proved. Sometimes people are later found to have been harmed.” Zietman, who is involved in the Massachusetts General trial, added: “I don’t think we’re doing harm (with proton therapy), but we don’t know. In some instances, proton therapy might be inferior to existing treatments, and the quality of life might not be as good.
Robert Foote, a radiation oncologist at the Mayo Clinic who is overseeing a $370m project that will bring accelerators to new centres in Minnesota and Arizona within the next four years, is also worried that some centres are adopting the proton beam therapy before enough research has been done and, possibly, for the wrong indications.
He worries that some centres with big commercial investors will be keen to recoup their investment fast by putting through a large volume of patients, especially with prostate cancer, rather than using the technology for those most likely to benefit, such as children, a focus at the non-profit Mayo Clinic.
Foote says that two models of proton care have emerged in the US: “one to make money—the other to provide the best care possible for the people who need it.”
Cite this as: BMJ 2012;344:e2488
Competing interests: The author has completed the ICJME unified disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declares no support from any organisation for the submitted work; no financial relationships with any organisation that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work.
Provenance and peer review: Commissioned; externally peer reviewed.