Download External Beam Radiation Therapy (EBRT) External beam radiation

External Beam Radiation Therapy (EBRT)
External beam radiation therapy (EBRT) involves precision delivery of high energy radiation
beams to the tumor while sparing normal surrounding healthy tissue.
EBRT has use as both primary definitive treatment with or without brachytherapy for prostate
cancer that has not spread, as well as supplemental treatment after prostatectomy when PSA
levels are higher than 0.2 ng/ml or when the pathology report after prostatectomy surgery
identifies positive margins, or stage 3 cancer (extracapsular spread or spread to seminal vesicles)
or when Gleason score 9 or 10 is identified.
The goal of all radiation therapy technologies is to safely deliver the highest possible doses of
radiation to the cancer and the lowest possible doses to normal structures, thereby achieving the
highest possible cancer rates and the fewest possible side affects.
Receiving external beam radiation is similar to having an X-ray taken. It is a painless, bloodless
procedure that rarely causes side effects during or after treatment. On rare occasions, patients
may experience mild increase in urinary frequency or mild fatigue, both of which are easily
controllable with life-style changes or medications, and almost always resolve within a few
weeks of completing treatments. In an effort to minimize side effects, the treatments are typically
given daily Monday through Friday for a number of weeks.
The radiation beam comes from a machine located outside of your body that does not touch your
skin or the tumor. Using sophisticated treatment planning software, your radiation oncology
treatment team of physicists and planners along with Dr. Shasha customizes the configuration
and intensity of radiation beams to most effectively treat your tumor while sparing the normal
surrounding organs (intestines and urinary bladder).
Click here to view a comparison chart of treatment options and side effects between
Brachytherapy (seeds) versus Radiation versus surgery (prostatectomy).
Click here to see Patient Cure Rates with Brachytherapy ("Seeds").
EBRT involves using “beamlets” of high energy photons created by sophisticated computer
controlled, robotic machines called linear accelerators (“linacs”) (Figure 7). Treatments with
sculpted modulating energy beams are precisely delivered with the patient is comfortably lying
still while the machine circumferentially rotates around. Depending on the technology employed,
either a single circumferentially delivered continuous beam of radiation or several individual
beams of radiation are delivered to converge on the prostate gland and seminal vesicles in the
center of the patient like spokes on a wheel (Figure 8).
The daily (Monday-Friday) treatment is delivered daily by staff called “radiation therapists” at
approximately the same time on an outpatient basis for 5 to 9 weeks, although newer techniques
are evolving to condense treatment time to 1 to 4 weeks. Therapists are responsible for
positioning you and for delivering treatment with the linear accelerators. In order to maintain
quality, therapists will verify your identification prior to each treatment and there will always be
at least 2 therapists present at the linear accelerator for all of your treatments. Daily treatment
time typically takes 2-3 minutes, with an addition 5-10 minutes for setting up, and 5-10 minutes
for getting dressed and undressed – so that total time in the department is typically 30 minutes.
You will be alone in the treatment room while treatment is being delivered, but will be able to
communicate via video monitors and speakers with therapists who will be watching your
treatment a few feet away at the treatment console. While the machine is rotating around, you
will hear a ticking noise which is the sound of the lead shields moving in the machine in order to
precisely target your prostate and avoid treating healthy tissues.
Figure 7: Linear accelerator rotating around the patient while precisely delivering radiation to converge
centrally on the prostate gland like spokes on a wheel. Change text in Figure 8: Computer-generated
Image Guided Radiation Therapy plan demonstrating “spokes on wheel” radiation delivery to
conformally target the prostate while sparing rectum and bladder.
Figure 8: Computer-generated Image-G.

Evolution of External Beam Radiation Therapy EBRT technologies
o Three-dimensional Conformal Radiation Therapy (3dCRT)
o First developed in the early 1990’s 3dCRT was the by-product of the
technological revolution of that time that integrated newly invented radiation
therapy high-energy linear accelerators (“linacs”), computed tomography (CT)
scans and computer hardware and software. Consequently, for the first time ever,
precise targeting was made possible, as well as safe escalation of radiation doses
which resulted in improved cancer control rates and decreased toxicity compared
to earlier treatments used prior to 3dCRT.
o Intensity-Modulated Radiation Therapy (IMRT)
o The realization that doses higher than safely achievable with 3dCRT were often
needed to cure prostate cancer stimulated the rapid technologic evolution to
develop the next generation of computer planning and controlled delivery of
radiation treatments that would more precisely target the prostate and safely
enable delivery of even higher doses of radiation, while further reducing radiation
dose to normal surrounding tissues. This was accomplished in part by modulating
the intensity of radiation being delivered (rather than the constant intensity of
energy beams used by 3dCRT). Thus, the name “intensity-modulated” radiation
therapy.
o Image-Guided Radiation Therapy (IGRT)
o IGRT is the newest technology,and was developed because patients commonly
move during treatment, and because the prostate always moves with normal
respiration, and because anatomy frequently varies with the fullness of urinary
o
o
o
o
bladder and intestines. The goal of IGRT is to eliminate uncertainty daily just
before each treatment is delivered by evaluating patient conditions at the time of
treatment and either altering the patient position or adapting the treatment plan
with respect to anatomical changes that occur during the course of treatment.
Image guided radiation therapy (IGRT) signifies radiation therapy that uses image
guidance with CT or x-rays for prostate localization before and after treatment to
identify and correct problems arising before and during treatment from variation
in patient setup and anatomy, including shapes and volumes of the treatment
target(s), organs at risk, and surrounding normal tissues.
Stereotactic Body Radiation Therapy (SBRT)
SBRT is an emerging technology still under investigation with encouraging
preliminary results for prostate cancer that takes advantage of millimeterprecision targeting now routinely possible with IGRT. SBRT delivers much
higher doses for each daily treatment than IGRT. Consequently, the total number
of daily treatments is reduced, enabling total treatment time to be condensed from
8-9 weeks with IGRT down to 1-4 weeks with SBRT. Safety and efficacy of
SBRT and appropriate patient selection will be determined by results of ongoing
studies in the near future. Cyberknife is a brand of SBRT that is frequently used
by itself for patients with early stage prostate cancer confined to the prostate or in
combination with another therapy, such as external beam radiation for patients
with disease that extends beyond the prostate. Long-term results with SBRT or
cyberknife are needed in order to recommend this treatment, especially for
younger patients or those with intermediate or high-risk cancer.
Side effects (and management):
With recent advances in Image Guided Radiation therapy, side effects during or
after treatment are generally rare , mild, and transient. When side-effects occur,
they typically begin in the third week of treatment, increase slightly during
treatment, then resolve within 4 weeks of completing treatment. There should be
NO nausea, vomiting, or skin changes and you will be able to continue all normal
activities. In fact, for most patients, the most difficult part of therapy is making
time in their schedules for daily treatments. Of course, we will do our best to
accommodate your scheduling needs to minimize inconvenience. You will see
your radiation oncologist weekly during treatment to answer any questions and to
treat any side effects. After treatment is complete, be sure to see your urologist
and your radiation oncologist within 4 weeks after your procedure for routine
symptom evaluation and cancer surveillance, then every 3 to 6 months, thereafter.
Slight increase in the frequency of urination, particularly at night time or weak
urinary stream or hesitation with urination (take alpha-blocker medication
(Flomax/tamsulosin, Uroxatrol/alfuzosin, Cardura/doxazosin, Hytrin/terazosin) or
other medications as prescribed by your doctor.
o Mild burning with urination (take Tylenol (acetominophen) as needed.
o Slight increase in the frequency of urination, particularly at night time or weak
urinary stream or hesitation with urination (take alpha-blocker medication
o
(Flomax/tamsulosin, Uroxatrol/alfuzosin, Cardura/doxazosin, Hytrin/terazosin) or
other medications as prescribed by your doctor.
o Mild constipation or loosening of stools, frequent small stools, or increased
flatulence (avoid coffee and decaffeinated coffee, and take bulk laxative such as
Metamucil or Citrucel.
o Difficulty achieving an erection (ask your doctor if you may take a medication
such as Viagra, Levitra, or Cialis, any of which are equally effective in restoring
erections in approximaterly 85% of patients potent prior to implant.
o
o
o
o
o
o
o
o
o
Other EBRT Recommendations
See your urologist and your radiation oncologist within 4 weeks after completing
your treatment for routine symptom evaluation and for cancer surveillance, then
every 3 to 6 months, thereafter
Resume normal diet, and physical and work activities including exercise
immediately as tolerated.
Continue urinary medications as recommended by your doctor.
Continue fiber powder (Metamucil or Citrucel) twice daily forever.
Loss of pubic hair may occur in the area treated, but is usually temporary. You
will not lose hair anywhere else.
Intimacy: it is important that you and your partner understand that your cancer is
not contagious and that intimate relations do not pose any threat to either of you
or to the outcomes of your treatment. Because of medications prescribed and/or
because of radiation treatments, you may notice less fluid coming out when you
ejaculate; this is normal, and expected, and not dangerous. It is vital that you and
your partner understand that radiation therapy and brachytherapy are NOT birth
control and that conception and full-term pregnancy can occur. If you notice a
decrease in the strength of your erections, you should ask your physician if you
may take an erectile enhancement medication such as Viagra, Levitra, Cialis, etc.,
that have been reported to restore erections in nearly all patients who were potent
prior to their radiation treatment(s); 10-year potency preservation with these
medications is expected in 85% of men who were potent prior to radiation
treatment.
Always call your radiation oncologist immediately for recommendations if blood
is seen in the stool.
Always ask your gastroenterologist to speak with your radiation oncologist prior
to doing a colonscopy.