question about proton therapy after conventional radiation - 1263592

Hi deern01,

There are many potential reasons why your radiation oncologist does not feel that your father is a candidate for proton beam radiation, including reluctance to re-radiate a previously radiated area, but you should not feel that he has missed a better option. As Dr. West described it:

“Proton beam therapy is a technique that allows radiation to be delivered to a particular depth within tissues and then stop, minimizing radiation “in front of” and “behind” the target point (I’ve heard proton beam therapy described as similar to a light saber, going out to a point and then stopping, while radiation would be more like a laser beam, affecting everything in its path — although I think the light saber analogy isn’t quite right in that proton beam radiation shouldn’t deliver much radiation leading up to the target point either). It does allow very detailed administration of radiation to tight areas and is particularly great around the eyes, and it’s also used for some rarer children’s cancers, I believe. It’s being used more and more for prostate cancer, but the problem is that it’s not clear that it provides benefits beyond many other better studied and more widely available tools.” – http://cancergrace.org/forums/index.php?topic=788.msg4102#msg4102

[continued in the next post]

JimC
Forum moderator

[continued from the previous post]

In the same thread, he went on to say:

"Proton beam radiation is unquestionably more expensive, but it’s not clearly better than conventional and still quite advanced radiation techniques like IMRT (intensity modulated radiation therapy) for lung cancer and most other common cancers. The challenge is that it is marketed very aggressively because the centers cost so much that the people need to recoup their $200M investments, which you can’t do if you limit yourself to the few clinical situations in which proton beam RT is actually a clearly superior choice. So you market the hell out of it, provide vague innuendos that newer and more expensive is better, and take advantage of the fact that people are inclined to believe that more expensive must be superior. You can certainly use some dizzying physics theories to provide a plausible smokescreen in the absence of actual evidence it’s better.

It’s possible that additional studies will ultimately demonstrate that proton beam radiation is superior for lung cancer and other common cancers, but not necessarily. A study in prostate cancer showed it was clearly NOT more effective and was associated with worse side effects than more readily available IMRT, perhaps because the more sophisticated software for more mature radiation platforms allows better tailoring of the radiation field than most current proton centers, which have more rudimentary software to guide the process.

This isn’t sour grapes, by the way. Our own center was approached as the first choice place for a proton beam facility by a private group wanting to build in Seattle, but our radiation oncologists saw that the cost couldn’t be justified by the limited group of patients best served by protons. They concluded you would need to market it to people beyond its demonstrated place, and that’s exactly what’s happening."

JimC
Forum moderator

This still reflects my view on the issue. Proton beam may ultimately prove superior to other radiation methods, but not necessarily. In the meantime, last year we saw an example of "newer is NOT better" when a higher than standard dose of radition (74 Gray) was tested head to head with standard dose (60 Gray), all combined with concurrent weekly chemo. I think many, probably most, radiation oncologists presumed the higher dose must be better because it was feasible and more MUST be better, but that wasn't what the study showed. In fact, it showed that the higher dose was significantly WORSE than standard dose radiation.

We may find that proton beam radiation follows the same pattern. Not necessarily, but we definitely can't presume that it's significantly better just because people who profit from marketing it make vague suggestions that it's better without actually having good clinical evidence to illustrate that.

-Dr. West