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Proton beam radiation is an older technology that has actually been in use since the 1950s. Rather than
treating cancer with photons, as occurs with IGRT, men are simply treated with a different type of radioactive particle, called
protons. Because it is new to north Florida, some men have been interested in comparing proton beam therapy to newer and more
precise forms of treatment, such as prostate seed implants and IGRT. The safety and effectiveness of seed implants and IGRT has been thoroughly studied in hundreds of scientific papers,
with superb long-term 15 year outcomes. In contrast, after 50 years of proton use, there is still remarkably very little published
data on its cure rates and complications. There are no studies reporting outcomes beyond 5 years after treatment with proton
beam. There are no studies showing long-term potency and incontinence rates. This data is critical for men with a long life
expectancy. A review of every published study on proton beam radiation shows that patients suffer much higher cancer recurrence
rates, are more likely to develop long term complications, and are at a greater risk of developing new cancers than those
treated with seed implants. In addition, proton beam therapy is very time consuming (9 weeks of daily treatment are required),
costly (more than $100,000), and not covered by many insurance plans. For these reasons, most major cancer centers throughout
the world have decided not to pursue the less effective proton beam technology and instead have focused their attentions on
more innovative and successful seed implant and IGRT programs for the optimal treatment of prostate cancer.
Proton Radiation - Increased Recurrence Rate
Will
seed implants improve my likelihood of being cured?YES! Our cure rates with seed implants are 20 to
40% better than the best results ever published with proton beam therapy. Seed implants have the unique advantage of having
the radiation placed directly into the cancer. The radiation is concentrated where it needs to be, without the unnecessary
high dose radiation of areas outside the prostate, as occurs with proton therapy. (see chart below)
A recent study from the largest proton center in the country at Loma Linda, California reported that for 1,225
men with prostate cancer, the 5-year success rate with proton therapy was only 73%. For those with high risk disease, the
success rate was only 43% (Slater, 2004) Tnfortunately, there have not been any studies looking at outcomes more than 5 years following proton beam treatment. This
is in comparison to our own recently reported long term study showing at 10 years, a 95% success rate with seed implants for
intermediate risk disease, and 83% success rate for high risk disease (Terk 2009). With the seeds being placed directly
in the prostate, higher doses of radiation can be given to the cancer, resulting in a much higher BED (biologically effective
dose). The 20-50% higher BED seen with seed implants results in much greater cancer killing. Seed implants allow the ultimate
concentration of radiation directly in the prostate, while still keeping surrounding areas at the lowest dose possible
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Proton Radiation - Increased Side Effects
Will I have fewer long term side effects with a seed implant?
YES - because high dose proton beam radiation is delivered externally from a machine, the radiation
still must enter the body from the outside and pass through organs like the bladder and rectum and hips to reach the prostate,
causing much greater side effects than seed implants. A study from a leading proton facility showed that following proton
radiation, 41% of men had long-term rectal bleeding and 47% had long-term bleeding with urination (Gardner, 2002). Long-term incontinence rates after proton radiation still remain unknown. In contrast to proton beam radiation, long
term side effects are very rare with seed implants. Using an intra-operative dosimetry technique, the likelihood of the seeds
migrating outside the prostate is less than 0.4%. Urinary incontinence occurs in less than 1% of men following a seed implant.
Other severe urinary problems are also very rare. (Zelefsky, 2007) Will seed implants allow for improved preservation of my erectile function?
YES - The best erectile function preservation rates are obtained with seed implants. By pinpointing the seeds
directly in the prostate, there is minimal effect on nerves that help control erections. Studies show that up to 90% of men
maintain their erectile function after a seed implant (Cesaretti, 2007). Erectile function has never been evaluated after proton beam radiation. Because proton radiation needlessly treats outside
the prostate where the nerves reside to a high dose, much greater impotency rates are expected.
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A. A dose map of a prostate being treated with protons shows the
excess radiation deposited outside the prostate. This is what causes the higher side effects. |
B. A similar dose map of a prostate being treated with a seed
implant shows no excess radiation outside the prostate, as the seeds radiate the prostate from within. |
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Proton Radiation - Dangers
Why is there a high risk of proton radiation causing a new cancer to
develop?Of great concern, the renowned radiation biologist Dr. Eric Hall reported that the physics of
proton radiation delivery causes excessive neutron contamination in the patient’s body. Neutrons are dangerous
nuclear particles that can damage normal organs. They are known to to increase the likelihood of developing potentially life-threatening
secondary cancers. (Hall, 2007). This risk of neutron contamination is much greater with proton radiation than with either IGRT or seed implants.
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Proton Radiation - Salvage Treatment
What are my treatment options if I have a recurrence of my
cancer after proton beam radiation?The Florida Center for Prostate Care has the largest published experience
in the world using seed implants to treat patients with recurrent cancer after prior radiation treatment. Several simple tests
and our review of your records help determine if you are a potential candidate for this highly specialized treatment.
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Questions to Ask if You are Considering Proton Radiation
Men with prostate cancer deserve answers
clearly supported by evidence published in medical journals. 4 questions you MUST ask your proton doctor if
you are considering proton beam treatment:1. Have you personally published your
10 year proton beam results in a medical journal or presented them at an international conference? 2. For my stage of
prostate cancer, what is the published likelihood that I will be cancer free 10 years after proton beam radiation?
(please show me the articles) 3. Why do experts report my risk for developing a new secondary cancer is greater after
proton beam radiation than prostate seed implants? 4. What is the 10 year published likelihood of maintaining
my erectile function and urinary control (continence) after proton beam radiation?
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1 Bittner - IJROBP, 2008
2 Zelefsky - IJROBP, 2007
3 Slater - IJROBP, 2004
4 Zietman - JAMA,
2005
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