Proton Therapy is Well-Tolerated In Prostate Cancer Patients

CHICAGO, Nov. 2 /PRNewswire-USNewswire/ -- Proton beam therapy can be safely
delivered to men with prostate cancer and has minimal urinary and rectal side
effects, according to a study presented November 2, 2009, at the American
Society for Radiation Oncology's 51st Annual Meeting in Chicago.

Researchers sought to determine if delivering higher doses of radiation with
proton therapy would cause early harmful side effects to urinary function
within the genitourinary system (GU) function and rectal function within the
gastrointestinal (GI) system.

"Proton therapy is becoming more popular as a treatment for prostate cancer,
but it is unclear at this point whether the long-term outcomes with proton
therapy will be better than those achieved with other treatments. These
protocols were designed to establish benchmark results with proton therapy
given with relatively high daily doses. At this point, we can say that early
tolerance of proton therapy has been excellent, with a very low rate of
urinary and rectal toxicity," Nancy Mendenhall, M.D., a study author and
medical director of the University of Florida Proton Therapy Institute in
Jacksonville, Fla., said. "This study shows that prostate cancer patients can
receive proton therapy with a very low likelihood of compromised urinary or
rectal function."

Proton beam therapy is a form of external beam radiation treatment that uses
protons rather than photons (X-rays) to treat certain types of cancer and
other diseases. The physical characteristics of the proton therapy beam allow
the radiation oncologist to deliver more radiation to the tumor with less
radiation to nearby healthy tissues.

During external beam radiation therapy, a beam of radiation (X-rays or
protons) is directed through the skin to the cancer and the immediate
surrounding area in order to destroy the main tumor and any nearby cancer
cells.

From August 2006 to October 2007, 212 prostate cancer patients enrolled in one
of three prospective trials to receive proton therapy. High-risk patients also
received the chemotherapy drug, docetaxol, followed by hormone therapy.
Researchers followed the patients for at least a year after treatment and
examined the genitourinary and gastrointestinal toxicity scores using both
International Prostate Symptom Scores (IPSS) and Common Toxicity Criteria for
Adverse Events (CTCAE, v. 3) for each patient.

Findings show that there was minimal early GU and GI toxicity on prospective
trials of proton therapy. Less than one percent of patients had severe Grade 3
genitrourinary side effects. There was a significant association between GU
side effects after treatment and patients' pretreatment urinary function. Less
than one-half percent of patients experienced Grade 3 gastrointestinal
toxicities. The most common gastrointestinal side effect was minimal rectal
bleeding, which was associated with the percentage of rectal wall receiving a
range of radiation doses. The incidence and severity of rectal symptoms were
also impacted by post-treatment colonoscopic interventions.

"These results are very encouraging. While some toxicities may occur later, we
are very pleased with the early toxicity profile in comparison with other
treatment options. Further follow-up will be necessary to ensure that these
men do not have any side effects that appear years after the treatment," added
Dr. Mendenhall.

For more information on radiation therapy for prostate cancer, visit
www.rtanswers.org.

The abstract, "Early Gi And Gu Toxicity In 3 Prospective Trials Of Proton
Therapy For Prostate Cancer," will be presented at a scientific session at
11:30 a.m. on Monday, November 2, 2009. To speak to one of the study authors,
Nancy Mendenhall, M.D., please call Beth Bukata or Nicole Napoli November 1-4,
2009, in the ASTRO Press Room at McCormick Place West at 312-791-7005 or
312-791-7006. You may also e-mail them at bethb@astro.org or
nicolen@astro.org.

SOURCE American Society for Radiation Oncology

Beth Bukata, bethb@astro.org, Nicole Napoli, nicolen@astro.org , 800-962-7876,
Press Room Phone - Nov. 1-4: +1-312-791-7005 or +1-312-791-7006, After Hours:
+1-703-474-0940