SAVI Brachytherapy for Early-Stage Breast Cancer

A Specialized Procedure Used for Short-Course Radiation Therapy

Strut-adjusted volume implant (SAVI) brachytherapy uses an implanted device that delivers radiation internally. Brachytherapy is also known as internal radiation therapy.

SAVI is often used after a lumpectomy (removing abnormal tissue or cancer from the breast) in those diagnosed with early-stage breast cancer. This type of brachytherapy is different from external beam radiation, which applies radiation from outside the body and can cause damage to underlying tissues of the breast, lung, and ribcage.

SAVI reduces the length of therapy from up to seven weeks for traditional whole-breast irradiation to just one week or less. This short-course approach is known as accelerated partial breast irradiation (ABPI).

In studies, ABPI was shown to improve cosmetic outcomes while remaining an effective treatment method and being generally well-tolerated by patients. People undergoing ABPI typically report fewer side effects than those who receive whole-breast irradiation.

This article will explain when SAVI is used, how it works, and what to expect from the procedure.

SAVI brachytherapy
 Verywell / Emily Roberts

Whom It's For

The aim of radiation therapy is to prevent breast cancer recurrence by killing off any remaining cancer cells. To conserve the breast and spare surrounding tissues, brachytherapy is increasingly used in stage 0, stage 1, or stage 2 breast cancer when the tumor is less than 3 centimeters (about 1.2 inches) in diameter.

Because the SAVI device volume is customizable, it can be used to treat cavities of varied sizes or irregular shapes after surgery.

How It Works

The SAVI system consists of a tube-like applicator (called a trocar), an expandable bundle of tiny catheters, and a computerized radiation delivery system. The bundled catheters are positioned around the applicator pole like the ribs of an umbrella.

Once the device is inserted through a small incision in the breast, the pole is partially retracted, causing the catheters to expand into a ball shape. The tiny catheters are soft and flexible, and able to conform to the shape of the surgical cavity, providing a snug fit.

The radiation dose can be individually controlled through each catheter, allowing precise targeting by the oncologist (medical doctor who is a cancer specialist). Once the round of therapy is complete, the internal catheters can be left in place until the next round.

According to a 2016 study in the journal Brachytherapy, SAVI-based APBI achieved a four-year survival rate of between 92% and 98% in the 250 women studied. Of these, only 2.3% experienced a cancer recurrence.

Potential Advantages

The SAVI device received 510(k) clearance from the Food and Drug Administration (FDA) in 2006. The classification is used for medical devices that are considered safe and "substantially equivalent" to similar devices in current use.

Compared to other methods of radiation therapy, advantages include:

  • Shorter treatment duration (five to seven days vs. five to seven weeks with whole-breast irradiation): This means less disruption to your schedule, less travel time, and fewer co-payments.
  • Reduced levels of radiation: With whole-breast radiation, healthy cells in the radiated area are affected along with the cancer cells, causing issues like skin burns and tissue thickening. APBI using SAVI brachytherapy is more precise in terms of the area it targets, which minimizes harm to surrounding tissues.
  • Less fatigue: Standard radiation may cause fatigue, but with brachytherapy, you should be able to go about life as usual.

As opposed to interstitial brachytherapy, which involves the insertion of multiple tubes (catheters) in and around a tumor, the SAVI system only requires a single entry point.

SAVI-based APBI, like other forms of brachytherapy, reduces many of the characteristic risks of external beam radiation. These include skin changes (which sometimes are permanent), hardening of breast tissue (called radiation fibrosis), spider veins (telangiectasia), changes in breast shape, localized nerve damage (brachial plexopathy), and damage to underlying bone and lung tissues.

Procedure

SAVI brachytherapy is a two-part procedure involving the implantation of the SAVI device and the actual radiation therapy delivered. This typically involves a team of providers, including a radiation oncologist (medical doctor who specializes in treating cancer patients with radiation), a dosimetrist (radiation oncology professional who creates a plan to deliver radiation doses), a radiation therapist (medical professional who assists in administering radiation), and a nurse.

Preparation

The SAVI device can be placed during the lumpectomy or afterward in a separate procedure. The latter can be performed as an in-office procedure or in an outpatient clinic.

Before insertion, the breast is evaluated with an ultrasound to determine the size and shape of the surgical cavity. Four different sizes of the implantable device are available.

If the procedure is done on an outpatient basis, a topical lidocaine anesthetic is used to numb the incision area. A sharp, tube-like trocar is then inserted into the breast under the guidance of an ultrasound (method that uses sound waves to produce images of structures within the body). Next, the SAVI device is fed through the trocar and expanded until it fully conforms to the space.

After the trocar is removed, the incision site is secured with sterile dressing; no sutures (stitches) are needed. Only a small bundle of catheter ends extends outside of the breast.

Radiation

Once the SAVI device is in place, you will go to your radiation oncologist to start treatment. The radiation is delivered twice daily for about five days in a specialized radiology facility. Some cancers may require only three to four days of treatment; others may need up to seven.

At this stage, the external catheter ends are individually connected to a machine called a high-dose radiation (HDR) afterloader. The device is programmed to feed tiny radioactive pellets, called brachytherapy seeds, into each tube. The appropriate radiation dose, measured in grays per hour (Gy/hr, which measures gamma ray intensity), is determined by the dosimetrist based on the lab findings.

The seeds are left in place for 10 minutes and then removed. Upon the completion of a dose, the seeds are withdrawn and reinserted six hours later, for a total of two treatments per day.

After your final round of radiation is complete, the oncologist will remove the SAVI device. This can be done with or without lidocaine in about two minutes. A Steri-Strip is used to close the incision site. A bandage or dressing is then placed on top and you'll be free to go. One or more follow-up visits will be scheduled to ensure that the incision is properly healed.

Side Effects

Compared to external beam radiation, the side effects of SAVI brachytherapy are far less significant. Fatigue is a common radiation-associated side effect and generally resolves within several days of the completion of therapy.

Other less common side effects include a change in skin color, skin dryness, and a loss of hair under the arm. If the treatment site was near the armpit, there may be swelling in that arm caused by lymphedema (lymph node obstruction).

As with any surgical procedure, there is a risk of infection. To avoid this potential issue, follow your healthcare provider's recommendations and these tips:

  • Wear a bra to keep the catheter ends securely in place.
  • Do not shower; take a sponge bath and wash your hair in the sink instead.
  • Avoid getting the breast wet.
  • Wash the catheter site daily or according to your healthcare provider's instructions, applying a light layer of antibiotic cream afterward.

In rare instances, the implantation of the SAVI device can cause a seroma, a pocket of fluid beneath the skin that may require drainage as well as a course of oral antibiotics.

Call your healthcare provider immediately if you develop a high fever, a pus-like discharge, and/or persistent or worsening pain, redness, and swelling around the incision site.

Contraindications

As attractive an option as SAVI brachytherapy may be, it is only indicated for the treatment of early-stage breast cancer. The procedure is best suited for women over age 50 whose tumors have well-defined margins. While not entirely contraindicated in younger women, SAVI may not be suitable for those under the age of 40 years old.

Some of the factors that might exclude you as a candidate include:

The presence of a positive lymph node is a contraindication for SAVI brachytherapy.

Summary

SAVI brachytherapy is often an effective treatment option for those with early-stage breast cancer. This type of internally delivered radiation typically provides improved treatment outcomes with fewer reported side effects compared to external, whole-breast radiation. Always discuss all available treatment options and potential side effects in-depth with your healthcare provider to determine the best option for your individual situation.

A Word From Verywell

SAVI brachytherapy is available across North America, but not at every cancer center. There may be factors that exclude you from treatment, but local availability shouldn't be one of them. If you live outside of a major urban center and have limited options for radiation therapy, you may want to consider traveling for the five- to seven-day course of SAVI brachytherapy rather than submitting to whole-breast irradiation closer to home.

Frequently Asked Questions

  • What does "SAVI" stand for?

    The term "SAVI" is short for "strut-adjusted volume implant." This implanted, specialized device is used to deliver internal radiation therapy (brachytherapy). The struts (parts of the device that can be adjusted in size) allow your radiation oncologist to expand the device to fit the breast cavity as part of treatment.

  • How long does it take to place a SAVI device?

    Often performed as an outpatient, same-day procedure, implantation of a SAVI device typically takes about 20 minutes. The procedure is done under guidance of ultrasound using a small incision to place the device.

  • How effective is SAVI?

    Though SAVI has a shorter treatment course and delivers less radiation to surrounding tissues, it has proven effective in treating early-stage breast cancer. This APBI delivery system is often well-tolerated by patients, who reported side effects (like fatigue) less often.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Lu SM, Scanderbeg DJ, Barna P, Yashar W, Yashar C. Evaluation of two intracavitary high-dose-rate brachytherapy devices for irradiating additional and irregularly shaped volumes of breast tissue. Med Dosim. 2012;37(1):9-14. doi:10.1016/j.meddos.2010.12.005

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  5. Food and Drug Administration. 510(k) premarket notification.

  6. Merit Medical Systems. Three-fraction SAVI brachytherapy: Reducing patient interactions during COVID-19.

  7. Sayan M, Wilson K, Nelson C, Gagne H, Rubin D, Heimann R. A novel schedule of accelerated partial breast radiation using intensity-modulated radiation therapy in elderly patients: survival and toxicity analysis of a prospective clinical trialRadiat Oncol J. 2017;35(1):32–38. doi:10.3857/roj.2016.01963

  8. Correa C, Harris E, Leonardi M, et al. Accelerated partial breast irradiation: Executive summary for the update of an ASTRO evidence-based consensus statement. Pract Radiat Oncol. 2017;7(2):73-79. doi:10.1016/j.prro.2016.09.007

Additional Reading
Originally written by
Pam Stephan
Pam Stephan is a breast cancer survivor.
Learn about our editorial process