Partial Breast Radiation (APBI)

Partial Breast Radiation

The benefit of radiation after lumpectomy for breast cancer is well established. There is a 30% local recurrence rate with surgery alone that is reduced to 8% after adjuvant radiation. Interestingly, when you look closer at the risk reduction, you find that the protective effect of radiation is only at the site of the original cancer. The likelihood of a new cancer in another part of the breast is NOT significantly reduced.

Accelerated partial breast irradiation (APBI) asks a very simple question. If the dose to the remaining breast is not beneficial then why give it? Initially it was because the technology didn’t exist for a painless, safe, and reliable technique. In 2002, a device called the Mammosite balloon finally answered the call.

An inflatable balloon is placed within the breast after the cancer is removed. A radioactive seed is delivered into the balloon twice a day for 5 days. After the last treatment the balloon is deflated and easily removed.

The total treatment time is dramatically reduced from 6-7 WEEKS down to 5 DAYS.

While this alone is a significant advance, there are other benefits as well. The treatment occurs from the inside out rather than outside in. This reduces the skin dosage allowing for a much more rapid delivery. There is also increased collaboration between surgeons and radiation oncologists in the planning, preparation, and delivery of radiation.

Also, while unlikely, if patients develop another cancer in the same breast that is outside of the APBI field, they are still candidates for breast conservation. Women treated with whole breast radiation who develop a new cancer in the same breast must have a mastectomy because further radiation is not an option.

Reuters: The National Breast Center has been named a “Center of Excellence” for APBI.

Highlights of the use of APBI:

  • FDA approved the first generation device,  named Mammosite in 2002
  • 5 year data from the initial safety trial of 43 patients demonstrates ZERO recurrences to date. (Incidence of recurrence from traditional radiation is 7.7% at 5 years).
  • Over 32,000 women treated to date. 82% report good to excellent cosmetic results and 100% would opt to have the same treatment again if needed.

Selection criteria are very important in determining which patients will have a predicted good outcome from APBI.

Common factors used to approve patients for the technique:

Node StatusNegative
SizeT1 (<2cn)
HistologyInvasive Ductal & focal DCIS


Placement timing and technique are also important to success. Original studies showed skin distance, cavity conformance, and inadequate pathologic margins or positive nodes as the most likely factors negating treatment. Placement is delayed until pathology is known to avoid having to remove the balloon because of an involved margin or unknown positive node. Ultrasound is used with every placement to obtain proper skin spacing and conformance of the tissues around the balloon. In the original study, 10% of patients were excluded prior to treatment because of these factors. Using the technique of delayed placement and ultrasound guidance has dropped this to only 2% in the National Breast Center series.

Learn more…

We currently use the SAVI catheter from Cianna Medical as we have found it enables better healing of the site post-radiation.  Historically, we used Mammosite and Contura brand balloon catheters, which are older generation products.

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