Partial Breast Brachytherapy
Radiation therapy is a common adjunct to breast cancer treatment or breast cancer removal (lumpectomy) to make sure all the cancer cells have been destroyed and prevent cancer from recurring. Radiation stops the cancer cells from repairing themselves and growing. Radiation therapy can be administered externally or internally. External radiation or whole-breast irradiation (WBI) targets the whole breast from the outside. Alternately, partial breast brachytherapy, also known as accelerated partial breast irradiation (APBI), is performed by delivering a high-dose of radiation through a radioactive material called a “seed” which is placed inside the breast tissue in or around the cancer site.
There are different types of partial breast brachytherapy, which include:
- Multi-catheter interstitial brachytherapy: Multiple catheters (narrow tubes) are inserted through multiple entry sites, through which the radioactive agent is introduced into the breast, at the site of the tumor.
- MammoSite: This device uses a single catheter with a balloon attached to its tip. The balloon is inflated with saline so that it expands and fits within the cavity left behind after lumpectomy. This requires the lumpectomy cavity to be globular in shape to accommodate the inflated balloon. The radiation source or seed is inserted into the cavity through the catheter and removed when the treatment is completed.
- Contura Multi-Lumen Balloon (MLB): The device includes a variably inflatable balloon with 5 catheters (also called lumens) within the balloon, through which the radioactive seeds are inserted. The five lumens allow your doctor to contour the radiation away from critical structures such as the skin or wall of the chest. The Contura system is used for irregularly shaped lumpectomy cavities. It uses a vacuum feature to accommodate the balloon within the available space and maximize the radiation delivery.
- Strut Assisted Volume Implant (SAVI): This is a multi-catheter device containing about 7-11 soft catheters (also called struts) to insert the radioactive seeds. These catheters are expanded once the SAVI is inserted into the lumpectomy cavity.
- Axxent: The devise employs an electronic brachytherapy procedure that uses a tiny X-ray tube to emit radiation instead of the radioactive seeds. The radiation can be turned on or off depending on the requirement of dose.
Partial breast brachytherapy is a highly successful treatment that is recommended for the following:
- Lymph nodes are negative for cancer
- Age of 50 years and above
- Small tumor (3 cm or lesser)
- Clear surgical margins around the tumor
- Specific amount of tissue between the skin and the catheter or balloon
The specific requirements vary with the type of device used. Some of the devices are customized for the shape of the lumpectomy cavity, intensity of radiation and duration of the dose. The size of the breast, and size and shape of the cavity are considered before selecting the appropriate partial breast brachytherapy catheter.
- Multi-catheter interstitial brachytherapy is not limited to the size or shape of the cavity.
- SAVI catheters are recommended for women with smaller breasts.
- MammoSite and Contura enable better control over dose, reducing the radiation to the skin and rib.
The placement of the partial breast brachytherapy catheter is performed as an outpatient procedure. Ultrasound or CT scan is used to evaluate the size and shape of the lumpectomy cavity, and its relation to your chest wall and skin. This will help your surgeon decide on the kind of brachytherapy most suitable for you.
Your surgeon makes a small incision and creates a tract in the breast to place the specific catheter inside the lumpectomy cavity. The balloon is then filled with saline (in case of a MammoSite or Contura) or the struts are expanded (in case of SAVI catheter) to fit snugly against the lumpectomy cavity. The implanted device is left in place during the entire course of treatment. During each session, the catheter is connected to a computer-controlled machine to deliver radiotherapy into the device. Once the treatment session is complete, the catheter is disconnected from the machine.
With the completion of the entire course of treatment, the catheter is removed and the incision is closed with a bandage.
After the catheter is placed, you will be able to go home immediately. A small portion of the catheter is left outside the breast until the treatment is completed. This will not be noticeable under your clothes. The region of the catheter should be kept clean and dry, so you should avoid taking regular showers. You can resume your normal activities, but refrain from vigorous exercises to avoid displacement of the catheter.
You normally will feel no discomfort during or after the treatment. However, you may sometimes experience:
- Breast pain
- Break-down of fat tissue in the breast
There are a number of benefits of partial breast brachytherapy treatment that can be considered when deciding on the best treatment option for you. These include:
- Shorter treatment period of five days (twice a day), when compared to the conventional external radiation method that requires 6 weeks
- Performed as an out-patient procedure
- Reduced exposure of normal, healthy tissues and organs to radiation as the treatment is given from inside, to the targeted area, and does not involve radiation traveling through normal tissues
- Minimal side effects
- Ability to continue normal activities during the treatment