Radiation Oncology Opinion

Proton Therapy: Equal Pay for Equal Gray

Cancer care increasingly needs to demonstrate the value of new technology.  While I believe that proton therapy has promise, currently I do not think it makes the cut to support widespread adoption.  Unless protons are proven to be better, treatment shouldn’t cost more than photons.

Proton therapy originated at the Harvard Cyclotron Laboratory more than 50 years ago.  Its unique beam characteristics allow radiation to stop very precisely, avoiding radiation to some nearby tissue.  Photons, or x-rays, are less precise, with a higher entry and exit dose, measured in Gray.   The promise is that protons have less side effects at the same radiation dose.

Until more recently, there were only two facilities in the US.  Now there are at least eleven centers with more planned in the near future.  With a price tag of $150 million dollars per facility, what do we get for $1.6 billion dollars spent?

Higher cost.

Medicare reimburses double for protons compared to photons.   Some insurance won’t cover proton therapy, considering it experimental.  We all bear the increased Medicare costs, and cancer patients may get stuck with any extra charges.

For some pediatric cancers such as medulloblastoma, the value is clear because it can lessen normal tissue exposure.  But there are only about 400 medulloblastoma patients annually.  The business case for proton center proliferation is prostate cancer, for which evidence increasingly suggests that many men with very low risk disease may not need any treatment .

To be fair, some vendors of proton therapy are less expensive, and the cost seems to be dropping.  But they’re not widely tested and there are questions about whether they will have the ability to match the technical abilities of more expensive versions.   So what do we get for more expensive equipment with higher treatment costs?

Possibly lower quality.

Despite the potentially superior beam characteristics of protons, quality may go down with rapid adoption for three reasons:

  1. Technology is only as good as the people using it.  More centers means less experience treating rare diseases with very complex equipment.

  1. Improvements in photon therapy may negate the proton advantage.  Recent data suggest that intensity modulated radiation therapy with photons may have less side effects than proton therapy for prostate cancer.

  1. Protons may miss cancer by being too precise, even in expert hands.  A Massachusetts General Hospital study found that proton therapy was associated with a higher risk of  dying from a spinal cord glioma compared to photons.

‘Equal pay for equal Gray’ means protons can be considered a reasonable but not superior alternative.   So don’t reimburse more for the same radiation dose unless it’s proven to be a safer, more effective treatment.  Some academic centers with strong pediatric oncology programs will see value, and currently that’s where this technology belongs.

Blue Shield of California may curb coverage because of the cost.  Don’t be surprised if other insurers follow around the country.

Proton therapy has definite potential to improve care beyond rare diseases; the technology deserves research funding to lower costs and identify which cancer patients truly benefit.  But should we allow widespread adoption before adequate research proves its value? What do you think?