SAVI Brachytherapy for Early-Stage Breast Cancer

A specialized procedure used for short-course radiation therapy

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SAVI brachytherapy

 Cianna Medical

SAVI brachytherapy is a suitable option for women with early-stage breast cancer. It involves the use of a specialized device that delivers radiation internally following a lumpectomy. Rather than exposing the breast to external beam radiation, which can damage underlying tissues of the breast, lung, and ribcage, the SAVI system delivers radiation from within using an implantable device that conforms to the shape of the surgical cavity.

SAVI brachytherapy reduces the duration of therapy from six to seven weeks for traditional whole-breast irradiation to just five to seven days. This short-course approach, known as accelerated partial breast irradiation (ABPI), offers better cosmetic results and nearly the same efficacy as whole-breast irradiation.

Who 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 (also known as internal radiation therapy) is increasingly used in women with stage 0, stage 1, or stage 2 breast cancer whose tumor is less than 3 centimeters (1.2 inches) in diameter.

Because the SAVI device is more customizable than a traditional balloon catheter, even women with small breasts may be eligible for this type of treatment. 

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-shaped configuration. The tiny catheters are soft and pliable, 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. 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 4-year survival rate of between 92 percent and 98 percent in the 250 women studied. Of these, only 2.3 percent experienced cancer recurrence.

SAVI vs. Other Forms of Brachytherapy

The SAVI device is a proprietary system that received 510(k) clearance from the U.S. 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.

It is considered a viable alternative to balloon brachytherapy, which employs an inflatable balloon filled with radioactive pellets to deliver radiation from within.

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 characteristics risks of external beam radiation. These include skin changes (sometimes permanent), hardening of breast tissue (radiation fibrosis), spider veins (telangiectasia), breast malformation, 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 oncologistdosimetristradiation therapist, and 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 configuration of the surgical cavity. Four different sizes of the implantable device are available. Because of its elliptical shape, the device is aligned with the long axis of the cavity.

If performed as an outpatient procedure, 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. 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 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 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), 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 re-inserted 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 would 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 profound. Fatigue is the 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 the contiguous arm caused by lymphedema (lymph node obstruction).

As with any surgical procedure, there is a risk of infection. To avoid this:

  • 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 as per your doctor's instruction, applying a light layer of antibiotic cream after.

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 doctor 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 50 whose tumors have well-defined margins.

Among some of the factors that might exclude you as a candidate:

While not entirely contraindicated in younger women, SAVI may not be appropriate given the risk of cancer recurrence. Younger women, particularly those under 35 at the time of their diagnosis, face a higher risk of recurrence simply by virtue of the additional years they are expected to live.

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 simply because no other local options are available.

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