Page 13 - Layout 1
P. 13
MEN’S
HEALTH
Adenocarcinoma of the prostate, or “prostate cancer,” remains charged catheter-free in 2-3 hours. With a half-life of 60 days
the No. 1 cancer diagnosed among American males as well as the for the more commonly-used I-125, there is a slow release of lo-
second most common cause of cancer deaths among American calized radiation over 8-10 months conforming to the prostate,
men. biologically very well-suited for a slow growing cancer like
prostate cancer. Increased voiding symptoms and a slight increase
Despite the emergence of robotic radical prostatectomy, radical in stool frequency last several months in most, but incontinence
prostatectomy is still associated with high rates of mild to severe is uncommon, and long term erectile dysfunction is less likely
incontinence (up to 20 percent or more) and erectile dysfunction with brachytherapy than with surgery or IMRT.
(up to 50 percent), as well as failure to cure, with at least bio-
chemical failure and/or progression of clinical disease in 20-50 Brachytherapy is particularly well-suited for the patient who
percent depending on individual risk factors and stage at diag- lives an hour or more away from a treatment center, or those not
nosis. Those that progress after prostatectomy then usually receive wanting to disrupt their work or social schedule by the longer
adjuvant external radiation and some progress to androgen block- treatment time of IMRT or the time for recovery after surgery.
ade and often second-line treatments for advanced disease. Myths that younger men should have surgery instead of
brachytherapy are not supported by any published literature.
Treatment options With a post-treatment positive biopsy rate of < 1 percent in ex-
Two commonly used radiation options are available, namely perienced hands, local disease recurrence is uncommon, with bio-
chemical failures usually due to disease that was outside the
Intensity Modulated Radiation Therapy (IMRT) and Low Dose treatment field at the time of treatment.
Rate (LDR) Trans-perineal Brachytherapy, often referred to as a
“seed implant.” Part of the success of brachytherapy is likely due to the ex-
tended range and margins of the treatment field compared to
IMRT represents the evolution of 1990’s “external beam” to IMRT or radical prostatectomy. The latter two are roughly lim-
CT-guided gating or blocking of the beam at the margins of the ited to the capsule of the prostate. Brachytherapy, because of the
target area to better avoid radiating surrounding tissues (bladder low dose rate nature, allows a margin of 4-5 mm outside the
and rectum). However, IMRT still requires 9 weeks of daily treat- prostate that is at 145 Gray, with a margin of 8-10 mm that is
ment and the dose delivered (75 Gray) is only slightly higher than delivered at 110 Gray. Thus, much higher doses are delivered out-
the dose required to kill prostate cancer (65-70 Gray). Attempts side the prostate than with IMRT, likely treating what might be
to increase the dose to 80 Gray were aborted due to high rectal microscopic disease that would otherwise be recognized as “pos-
toxicity. itive margins” after prostatectomy, or rising PSA and biochemical
failure after IMRT.
Low Dose Rate Brachytherapy, introduced in 1986 and refined
since, remains a highly effective modality in treating localized Figure 2 (following page) shows one of several figures from a
prostate cancer, with meta-analyses showing higher biochemical huge meta-analysis by the Prostate Cancer Treatment Foundation
freedom from relapse than with surgery or external radiation (Fig- showing biochemical cure with different treatment modalities
ure 1). from all published papers since 2000 culled for quality, this one
showing freedom from biochemical recurrence (rising PSA post
Brachytherapy has the distinct advantage of being delivered by treatment) in “low risk” disease. Similar stratification is noted in
a single outpatient treatment, requiring about one hour in the “intermediate” and “high risk” disease patients. For all three risk
operating room to implant the radioactive elements, with most levels, meaning good, moderate, or bad and aggressive cancers,
patients able to return to work or nearly full activities the next brachytherapy results published in peer-reviewed literature were
day. The physics treatment plan is individually designed using an superior to external radiation and surgery. These are readily avail-
outpatient trans-rectal ultrasound study in which a 3-dimensional able on an interactive web-page at www.pctrf.org.
model of the prostate is created. Titanium-encapsulated I-125
(Iodine) or Pd-103 (Palladium) elements (or “seeds”) are stranded National trends
together and preloaded into needles that are delivered to the fa- How does all this translate to current treatment paradigms?
cility for implantation by the team, including both a radiation
oncologist and a urologic oncologist working together in the OR. National trends over the last 10-12 years have seen a decrease in
After the one hour implant procedure, most patients are dis- continued on page 14
visit us at www.bcms.org 13
