Michelle Wallace, Presenter: Grant, Hologic, Inc

Alvaro Martinez MD, Abstract Co-Author: Nothing to Disclose

Peter Y Chen MD, Abstract Co-Author: Nothing to Disclose

Mihai Ghilezan MD, Abstract Co-Author: Nothing to Disclose

Pamela Benitez MD, Abstract Co-Author: Speakers Bureau, Hologic, Inc

Eric Brown MD, Abstract Co-Author: Nothing to Disclose

Frank A. Vicini MD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Analysis of short-term toxicity and cosmetic outcome in patients with early stage breast cancer treated with the MS using a 2-Day dose schedule.

This is a phase II non-randomized prospective trial. From March 2004 - August 2008, 45 patients were treated with MS using a 2-Day dose schedule consisting of 28 Gy delivered in 4 fractions to a depth of 1 cm from the applicator surface, and > 6 hours was required between fractions. Eligibility included age > 40, tumors 8 mm skin to balloon spacing (SS). Radiation dermatitis, breast pain, edema, hyperpigmentation, hypopigmentation, induration, telangiectasia, fat necrosis (FN), rib fracture, infection, and persistent seroma were evaluated at 6 mo using the NCI CTAE v3.0. Cosmesis was documented at > 6 months. Fisher’s exact analysis was completed to determine the effect of placement timing (open vs. closed cavity), technique (SET vs. Lateral), balloon volume ( 60 cc), catheter size (4-5 cm vs. 5-6 cm) and chemotherapy on developing infection or seroma.

The median age was 66 years (48-83), median balloon volume 60 cc (35-110), and median SS 12 mm (8-24). The median FU was 11.4 months (5.4-48 mo), and 96% have FU > 6 mo. Overall, grade II/III toxicity rates were minimal. At 6 months (n=43), grade II radiation dermatitis, induration, and hypopigmentation were 2% (n=1), grade III breast pain was reported in 2% (n=1). Infection was 16% (n=7) at 6 mo. Of these pts, only 4% (n=2) had a positive culture, whereas the others were treated empirically due to brisk erythema. Persistent seroma > 6 months was 30% (n=13). FN was seen in 9% (n=4), but only 1 pt required treatment. Rib fracture was seen in 5% (n=2). Cosmesis was good/excellent in 96% and fair in 4%. Statistically significant factors for infection were SET technique (p=0.016), balloon volume > 60 cc (p=0.011), and 5-6 cm catheter (p=0.001). Factors for seroma were open cavity placement (p=0.021), SET technique (p=0.001), balloon volume > 60 cc (p=0.013), and catheter size 5-6 cm (p=0.002). Chemotherapy was not a significant factor.

Treatment with the MammoSite using a 2-Day dose schedule has resulted in a less than 10% grade II/III chronic toxicity rates, except for seroma.Good/excellent cosmesis was seen in 96% of patients. Short-term results indicate that the 2-Day dose schedule is a safe and well-tolerated accelerated partial breast irradiation option with toxicity profile similar to that of a 5-Day program.

Wallace, M, Martinez, A, Chen, P, Ghilezan, M, Benitez, P, Brown, E, Vicini, F, et al, , A Report of Safety and Short Term Tolerance in Patients Treated with the MammoSite Balloon Applicator (MS) Using a Two-Day Dose Schedule.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/7000436.html