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36

NCCN Guidelines for Patients

®

Prostate Cancer, Version 1.2016

4 Overview of cancer treatments

Radiation therapy

Radiation therapy

Radiation therapy is a cancer treatment that uses

high-energy rays. The rays damage DNA. This either

kills the cancer cells or stops new cancer cells from

being made. Radiation can also harm normal cells.

Radiation therapy is an option for many men with

prostate cancer. Radiation therapy may be given to

your pelvic lymph nodes as well as to your prostate.

The two ways to give radiation are discussed next.

External beam radiation therapy

Most often, EBRT (

e

xternal

b

eam

r

adiation

t

herapy)

is the method used to treat prostate cancer. This

method delivers radiation from outside your body

using a large machine. The radiation passes through

your skin and other tissue to reach the tumor.

Simulation

Treatment planning with a simulation session is

needed. During simulation, pictures of the tumor will

be taken with an imaging scan. Pictures are taken

after your body is moved into the position needed for

treatment.

Using the scans, your treatment team will plan the

best radiation dose, number and shape of radiation

beams, and number of treatment sessions. Beams

are shaped with computer software and hardware

added to the radiation machine. Radiation beams are

aimed at the tumor with help from ink marks on the

skin or marker seeds in the tumor.

Receiving treatment

During treatment, you will lie on a table in the same

position as done for simulation. Devices may be used

to keep you from moving so that the radiation targets

the tumor. You will be alone while the technician

operates the machine from a nearby room. He or she

will be able to see, hear, and speak with you at all

times.

As treatment is given, you may hear noises. One

session often takes less than 10 minutes. EBRT is

given 5 days a week for about 8 to 9 weeks, although

there is growing interest in shortening the length of

treatment.

Often, ADT (

a

ndrogen

d

eprivation

t

herapy) is used

with EBRT. ADT is described later in this chapter.

Many studies have shown that adding ADT to EBRT

improves treatment outcomes when prostate cancers

are more aggressive. ADT has side effects so it

shouldn’t be used unless needed. Some men require

short-term (4 to 6 months) ADT. Other men are on

ADT for 24 to 36 months.

Radiation techniques

There are multiple types of EBRT. For prostate

cancer, 3D-CRT (

three

-

d

imensional

c

onformal

r

adiation

t

herapy) or IMRT (

i

ntensity-

m

odulated

r

adiation

t

herapy) may be used. In 3D-CRT, the

radiation beams match the shape of your tumor to

avoid healthy tissues. IMRT is a more precise type

of 3D-CRT that may be used especially for more

aggressive prostate cancer. The radiation beam is

divided into smaller beams, and the strength of each

beam can vary.

The prostate can slightly shift within the body. Tumors

may also change shape and size between and during

treatment visits. IGRT (

i

mage-

g

uided

r

adiation

t

herapy) can improve how well 3D-CRT and IMRT

target the tumor.

IGRT uses a machine that delivers radiation and also

takes pictures of the tumor. Pictures can be taken

right before or during treatment. These pictures are

compared to the ones taken during simulation. If

needed, changes will be made to your body position

or the radiation beams.

There are different types of radiation beams. 3D-CRT

and IMRT are x-ray–based treatments. They use