Brachytherapy

Brachytherapy

Brachytherapy, also known as internal radiation, is another way to deliver radiation
therapy. Instead of aiming radiation beams from outside the body, radioactive seeds or
pellets are placed into the breast tissue next to the cancer. It is often used in patients who
had BCS as a way to add an extra boost of radiation to the tumor site (along with external
radiation to the whole breast). It may also be used by itself (instead of radiation to the
whole breast). Tumor size, location, and other factors may limit who can get
brachytherapy.
There are different types of brachytherapy.
Interstitial brachytherapy: In this approach, several small, hollow tubes called
catheters are inserted into the breast around the area that the cancer was removed and are
left in place for several days. Radioactive pellets are inserted into the catheters for short
periods of time each day and then removed. This method of brachytherapy has been
around longer (and has more evidence to support it), but it is not used as much anymore.
Intracavitary brachytherapy: This is the most common way to give brachytherapy in
breast cancer patients and is considered a form of accelerated partial breast irradiation. A
device is put into the space left from BCS and is left in place until treatment is complete.
There are several different devices that can be used: MammoSite®, SAVI®, Axxent®, and
Contura®. They all go into the breast as a small catheter (tube). The end of the device
inside the breast is then expanded so that it stays securely in the right place for the entire
treatment. The other end of the catheter sticks out of the breast.
For each treatment, one or more sources of radiation (often pellets) is placed down
through the tube and into the device for a short time and then removed. Treatments are
given twice a day for 5 days as an outpatient. After the last treatment, the device is
collapsed down again and removed.
Early studies of intracavitary brachytherapy as the only radiation after BCS had
promising results, but didn’t directly compare this technique with standard whole breast
external beam radiation.

A recent study comparing outcomes between intracavitary brachytherapy and whole
breast radiation after BCS found that women treated with brachytherapy were twice as
likely to go on to get a mastectomy of the treated breast (most likely because cancer was
found again in that breast). The overall risk was still low, however, with about 4% of the
women in the brachytherapy group needing mastectomy versus only 2% of the women in
the whole breast radiation group.
This study raises questions about whether irradiating only the area around the cancer will
reduce the chances of the cancer coming back as much as giving radiation to the whole
breast. More studies comparing the 2 approaches are needed to see if brachytherapy
should be used instead of whole breast radiation.
Intracavitary brachytherapy can also have side effects, including redness, bruising, breast
pain, infection, and a break-down of an area of fat tissue in the breast. As with whole
breast radiation, weakness and fracture of the ribs can also occur.