Study: SAVI increases accelerated partial-breast irradiation eligibility

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The multichannel single-entry brachytherapy device, the Strut-Adjusted Volume Implant (SAVI, Cianna Medical), can safely allow an increase in eligibility for accelerated partial-breast irradiation (APBI) compared to balloon brachytherapy or 3D conformal radiation, according to a study published June 18 in the International Journal of Radiation Oncology, Biology and Physics.

Catheryn M. Yashar, MD, from the departments of radiation oncology and surgery at the University of California, San Diego (UCSD) in La Jolla, Calif. and colleagues conducted their study to follow up initial patients who received the treatment by SAVI, a device designed to allow dose modulation to minimize normal tissue dose while simultaneously maximizing target coverage.

Researchers collected data on the 102 patients treated at Arizona Oncology Services in Phoenix and UCSD from November 2006 through March 2009. The researchers included women 40 years and older (average age, 60.5 years) with invasive breast cancer or ductal carcinoma in situ and a tumor size of 3 cm or less. Each patient underwent a lumpectomy and axillary lymph node evaluation with either sentinel lymph node biopsy or full axillary dissection, and the device was inserted through a separate incision or the original lumpectomy scar as an outpatient procedure.

Patients were followed up every three to four months over the course of the first year of the study for toxicity and recurrence, and an ipsilateral mammogram was performed six months after surgery. At the follow-up marks, patients were treated with hormonal therapy, chemotherapy or both depending on the physician’s findings.

At the 21 month follow up, Yashar and colleagues determined: “The overall dosimetry was outstanding (median percent of target volume receiving 90 percent  of the prescription dose was 95.9 percent, volume of target receiving 150 percent of the prescription dose was 27.8 mL and volume of target receiving 200 percent of the prescription dose was 14.0 cm 3).”

In addition, no devices had to be removed prior to the end of the treatment. Patients with simultaneous limitations on the skin and chest wall were found to also have low rib and lung dose.

Reoccurrence occurred in one patient after follow up, telangiectasia developed in two patients (1.9 percent), Grade 1 hyperpigmentation developed in 10 patients (9.8 percent) and fibrosis developed in 16 patients (15.5 percent), with two experiencing Grade 2 fibrosis (1.9 percent). The authors also noted that currently, there have been two incidences of symptomatic seromas (1.9 percent), two cases of asymptomatic fat necrosis occurring at one year or greater and seen on routine imaging (1.9 percent). Of the patients, 5 percent were deemed ineligible for any balloon brachytherapy.

The device was well tolerated by all patients, and study results demonstrated that SAVI safely allows an increase in patients eligible for single-entry APBI over balloon brachytherapy or 3D conformal radiation, concluded the researchers.