Brachytherapy is a radiation
therapy that can be used as a prostate cancer treatment.
Sometimes referred to as interstitial radiation therapy,
seed therapy, or seed treatment, prostate brachytherapy
is capable of delivering high and concentrated doses
of radiation to the prostate gland.
Radiation’s Role in
the Treatment of Prostate Cancer
There are two types of prostate cancer radiation treatments:
external and internal which is also called interstitial.
Brachytherapy is interstitial, meaning treatment is
administered from “within the tissue.” External
radiation therapy involves the projection of photon,
neutron, or proton beams into the prostate gland from
a remote tool called the linear accelerator.
Radiation is used in the treatment of prostate cancer because exposure to radiation damages the DNA of cells. Cells will not be damaged unless they attempt to divide. Cancerous cells divide more quickly than
healthy cells. Therefore, healthy cells are able to
repair damage before undergoing mitosis, while cancerous
cells are not. Unfortunately, if the dose is strong
enough, healthy cells will be damaged to the point where
they cannot repair themselves before division. Interstitial
brachytherapy is able to deliver higher doses of radiation
to an area concentrated within the prostate gland
The History of Brachytherapy
The word ‘brachy’ is of Greek origin and
means ‘close’ or ‘short-distance.’
Prostate cancer brachytherapy literally means ‘therapy
that is administered from a short distance away.’
The concept of treating prostate cancer through internal
radiation therapy has been around since the early 20th
century. In the first half of the 20th century, as many
as 15 techniques were used involving the insertion of
radiation into the prostate gland. The success of these
treatments was limited.
In the 1960’s, the permanent
insertion of radioactive material into the prostate
gland was tried again. Two doctors tried the interstitial
insertion of gold-198 into the prostate gland in conjunction
with EBRT. Another center used Iodine –125 seeds
to irradiate the prostate through an incision. Unfortunately,
the success of these techniques was poor due to the
inability to see the prostate gland and the surrounding
organs. Not until around 1980, when doctors began to use a transperineal needle template, transperineal needles, and the transrectal ultrasound, did brachytherapy become a viable prostate cancer treatment.
Types of Prostate Brachytherapy
There are two types of brachytherapy that are used in
the treatment of prostate cancer: permanent low dose
radiation (LDR) and temporary high dose radiation (HDR).
LDR brachytherapy uses iodine-125 and palladium-103 stored in titanium cases usually referred to as brachytherapy seeds. As the name permanent brachytherapy suggest,
the seeds are permanently left inside the prostate gland.
Over the course of their radioactive lives, the seeds
will continuously emit low levels of radiation.
HDR brachytherapy uses a single
radioactive seed made of iridium-194 which is sometimes
referred to as an iridium wire. Soft flexible plastic
catheters are inserted through the perineum and into
the prostate gland. HDR brachytherapy entails an overnight
stay in the hospital during which a patient undergoes
two or three treatments with the wire through each catheter.