NCCN Guidelines for Patients
Rectal Cancer, Version 1.2017
After simulation, your radiation team will further
plan your treatment. Plans will be made by viewing
your CT scans on the treatment planning computer.
Your radiation oncologist will work closely with a
dosimetrist. They will plan the best dose, number and
shape of radiation beams, and number of treatments.
Your plan will be designed to treat the cancer while
sparing normal tissue.
Once your treatment plan is made, a set-up session
is needed. This session is sometimes called “port
film” day or dress rehearsal. The set-up session
occurs in the treatment room.
The radiation therapists will help place you in position
on the treatment table. The set-up marks will be used
for positioning. X-rays of the treatment fields will
be taken and viewed by your doctor. These x-rays
(or port films) are not for treatment. Your doctor will
approve treatment when your set-up is correct.
Treatment is given once a day on Monday through
Friday. Short-course radiation is finished in 5 visits.
Long-course radiation takes about 28 visits. Each
session can last between 10 to 30 minutes. In
general, treatment is received at the same time each
Before treatment, you will be placed into position.
If a mold was made, you will lie on it on top of the
treatment table. You must be in the same position
that was approved at the set-up session. X-rays of
your pelvis are used to assure this.
Conformal techniques are used for treating rectal
cancer. These techniques shape the radiation dose
to the cancer site to spare healthy tissue. 3D-CRT
delivers, from different angles, a photon beam that
matches the shape of the target.
Other types of conformal techniques are less often
used. IMRT (
is a form of 3D-CRT. It further modifies the beam’s
intensity during treatment. IMRT is used in certain
cancer with very precise, high-dose photon beams.
Treatment is finished in 5 visits. At this time, SBRT is
only used to treat some people with rectal cancer in
the spine, liver, or lungs.
During treatment, you will be alone in the room. A
therapist will operate 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. The machine will move around you to
different treatment angles. You will not see, hear, or
feel the radiation.
radiation inside your body during an operation.
Different methods can be used. However, the usual
method involves a device that is placed where the
tumor was. The radiation kills remaining cancer cells
in the tissue that was near the tumor.
IORT is a one-time treatment that is given while you
are still asleep. It is used to deliver extra radiation
if cancer cells may remain after surgery. This extra
radiation is called a boost. IORT uses radiation made
of electrons or lower energy x-rays. Electrons do not
travel far and are less likely to harm the tissue deep
to the treatment site.
Some cancer centers do not have an IORT machine.
In this case, a boost of radiation can be given
with EBRT, brachytherapy, or both. Brachytherapy
delivers radiation through radioactive objects that are
placed where the tumor was. The objects remain in
Overview of cancer treatments