Radiation therapy for breast cancer

Radiation therapy for breast cancer

Radiation therapy is treatment with high-energy rays or particles that destroy cancer cells.
Radiation to the breast is often given after breast-conserving surgery to help lower the
chance that the cancer will come back in the breast or nearby lymph nodes. Radiation
may also be recommended after mastectomy in patients with either a cancer larger than 5
cm, or when cancer is found in the lymph nodes.
Radiation is also used to treat cancer that has spread to other areas, for example to the
bones or brain.
Radiation therapy can be given in 2 main ways.
External beam radiation
This is the most common type of radiation therapy for women with breast cancer. The
radiation is focused from a machine outside the body on the area affected by the cancer.
The extent of radiation depends on whether mastectomy or breast –conserving surgery
(BCS) was done and whether or not lymph nodes are involved.
If mastectomy was done and no lymph nodes had cancer, radiation is targeted at the chest
wall and the places where any drains exited the body.
If BCS was done, most often the entire breast gets radiation, and an extra boost of
radiation is given to the area in the breast where the cancer was removed to prevent it
from coming back in that area. The boost is often given after the treatments to whole
breast end. It uses the same machine, but the beams are directed to aim at the site you
cancer was removed. Most women don’t notice different side effects from boost radiation
than from whole breast radiation.
If cancer was found in the lymph nodes under the arm, radiation may be given to this area
as well In some cases, the area treated may also include supraclavicular lymph nodes
(nodes above the collarbone) and internal mammary lymph nodes (nodes beneath the
breast bone in the center of the chest).
When given after surgery, external radiation therapy is usually not started until the tissues
have been able to heal, often a month or longer. If chemotherapy is to be given as well,
radiation therapy is usually delayed until chemotherapy is complete.
Before your treatments start, the radiation team will take careful measurements to
determine the correct angles for aiming the radiation beams and the proper dose of
radiation. They will make some ink marks or small tattoos on your skin that they will use
later as a guide to focus the radiation on the right area. You might want to ask your health
care team if these marks will be permanent.
Lotions, powders, deodorants, and antiperspirants can interfere with external beam
radiation therapy, so your health care team may tell you not to use them until treatments
are complete.
External radiation therapy is much like getting an x-ray, but the radiation is more intense.
The procedure itself is painless. Each treatment lasts only a few minutes, but the setup
time—getting you into place for treatment—usually takes longer.
Breast radiation is most commonly given 5 days a week (Monday thru Friday) for about 5
to 6 weeks.
Accelerated breast irradiation: The standard approach of giving external radiation for 5
days a week over many weeks can be inconvenient for many women. Some doctors are
now using other schedules, such as giving slightly larger daily doses over only 3 weeks.

Giving radiation in larger doses using fewer treatments is known as hypofractionated
radiation therapy. This approach was studied in a large group of women who had been
treated with BCS and who did not have cancer spread to underarm lymph nodes.
When compared with giving the radiation over 5 weeks, giving it over only 3 weeks was
just as good at keeping the cancer from coming back in the same breast over the first 10
years after treatment. Newer approaches now being studied give radiation over an even
shorter period of time. In one approach, larger doses of radiation are given each day, but
the course of radiation is shortened to only 5 days. Intraoperative radiation therapy
(IORT) is another approach that gives a single large dose of radiation in the operating
room right after BCS (before the breast incision is closed).
3D-conformal radiotherapy: In this technique, the radiation is given with special
machines so that it is better aimed at the area where the tumor was. This allows more of
the healthy breast to be spared. Treatments are given twice a day for 5 days. Because only
part of the breast is treated, this is considered to be a form of accelerated partial breast
irradiation.
Other forms of accelerated partial breast irradiation are described in the section,
“Brachytherapy.” It is hoped that these approaches may prove to be at least equal to the
current, standard breast irradiation, but few studies have been done comparing these new
methods directly to standard radiation therapy. It is not known if all of the newer methods
will still be as good as standard radiation after many years. This is why many doctors still
consider them to be experimental at this time. Women who are interested in these
approaches may want to ask their doctor about taking part in clinical trials of accelerated
breast irradiation now going on.
Possible side effects of external radiation: The main short-term side effects of external
beam radiation therapy are swelling and heaviness in the breast, sunburn-like skin
changes in the treated area, and fatigue. Your health care team may advise you to avoid
exposing the treated skin to the sun because it may make the skin changes worse. Most
skin changes get better within a few months. Changes to the breast tissue usually go away
in 6 to 12 months, but it can take up to 2 years.
In some women, the breast becomes smaller and firmer after radiation therapy. Having
radiation may also affect a woman's options in terms of breast reconstruction later on.
Radiation can also raise the risk of problems if it is done after reconstruction, especially
tissue flap procedures.Women who have had breast radiation may have problems
breastfeeding later on. Radiation to the breast can also sometimes damage some of the
nerves to the arm. This is called brachial plexopathy and can lead to numbness, pain, and
weakness in the shoulder, arm and hand.
Radiation therapy of axillary lymph nodes also can cause lymphedema (see the section,
"What happens after treatment for breast cancer?").

In rare cases, radiation therapy may weaken the ribs, which could lead to a fracture. In
the past, parts of the lungs and heart were more likely to get some radiation, which could
lead to long-term damage of these organs in some women. Modern radiation therapy
equipment allows doctors to better focus the radiation beams, so these problems are rare
today.
A very rare complication of radiation to the breast is the development of another cancer
called angiosarcoma (see the section, "What is breast cancer?"). These rare cancers can
grow and spread quickly.