BY RALPH BLUM
Following in the footsteps
of robotic surgeons, prostate cancer continues to go high-tech. Radiation, for
instance, is no longer just radiation. There are now numerous different ways to
deliver it. But the two methods I want to write about here are Intensity
Modulated Radiation Therapy (IMRT), and Proton Beam Therapy (PBT).
The predominant method in
the U.S. for the past decade is IMRT, a complex procedure that precisely
targets the prostate gland with multiple beams of high energy light (photons)
at different angles and intensities while significantly lowering the risk of
damage to the surrounding tissues and organs. This greater accuracy
in targeting also allows the therapist to maximize the radiation dose to the
tumor. IMRT has at least as effective a cure rate as surgery, and without the
risks and side effects of a major surgical procedure.
Having said that, I have
recently been checking out Proton Beam Therapy, a form of radiation that
targets the tumor with charged particles called protons. Several decades ago,
Loma Linda University in California was the first to begin administering PBT.
At that time, I had a friend who, at 55, developed prostate cancer and was one
of the first patients at Loma Linda when proton therapy was at a very early
stage. Bill has been free of cancer for over twenty years, and only recently
had a rise in PSA and is discussing further treatment.
Since then, thanks in part
to marketing hype, PBT is becoming increasingly popular. Now, M.D. Anderson,
Harvard, and the University of Florida in Jacksonville, are among the major
medical centers that have made PBT available. And The Mayo Clinic is
building two proton therapy centers (one in Rochester, one in Arizona) at
a cost of $380 million. Naturally PBT costs considerably more than IMRT.
When weighing treatment
options, patients generally consider two main factors: potential side-effects,
and successful outcome. So how do these two therapies measure up? Well, there
is considerable controversy in the urologic community. The good news is both
therapies have a high cure rate. Studies that have tried to compare IMRT with Proton
therapy indicate that the outcomes are quite similar and that the side effects
are comparable. No large randomized trials have been published that directly
compare patient outcomes with the different techniques. So in the end, a
treatment decision usually depends on such variables as patient preference and
It is reasonable,
therefore, to keep in mind that any medical center that has invested an
astronomical amount of money on equipment will end up wanting to use it.