Phase IV study evaluated the safety and device performance of an electronic brachytherapy system (Axxent Electronic Brachytherapy System) as adjuvant therapy for early-stage breast cancer.
Patients were ≥50 years of age and had completely resected invasive ductal carcinoma or ductal carcinoma in situ (<2.0 cm), with N0 M0 and negative microscopic margins of ≥1 mm. The balloon applicator was placed in a closed cavity with a balloon surface to skin distance of ≥7 mm. The prescribed dose was 3.4 Gy/fraction prescribed to 1 cm beyond the balloon surface twice daily (BID) for 10 fractions.
Of 65 patients consented, 21 (32%) were not eligible for treatment, and 44 (68%) were treated, with 6-months follow-up in 43 and 1-year follow-up in 36. The prescribed radiation treatment was successfully delivered in 42/44 (95.4%) patients; one was unsuccessful due to a controller issue and the other declined the final fraction following a balloon deflation. Side effects were as anticipated and generally manageable. Four CTCAE v3 grade 3 toxicities were reported: blistering (1), breast tenderness (1), and moist desquamation (2); all have resolved. The most common grade 2 toxicity was erythema. There were no device-related serious adverse events.
Early experience demonstrates that the electronic brachytherapy system performed as expected. Electronic brachytherapy has similar acute toxicity profiles to other high dose rate approaches for accelerated partial breast irradiation and offers the convenience of having the treatment in an unshielded room.
From the *Department of Radiation Oncology, Swedish Cancer Institute, Seattle, WA; †Department of Radiation Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, OK; ‡Department of Radiation Oncology, Rush University Medical Center, Chicago, IL; §Department of Radiation Oncology, Little Company of Mary Hospital, Evergreen Park, IL; ¶Department of Radiation Oncology, Wellstar Health System, Marietta, GA; ∥Department of Radiation Oncology, Rhode Island Hospital, Brown University School of Medicine, Providence, RI; **Department of Radiation Oncology, White Plains Hospital Center, White Plains, NY; ††Department of Radiation Oncology, Beth Israel Medical Center, New York, NY; ‡‡Department of Radiation Oncology, Mills Peninsula Hospital, San Mateo, CA; §§Department of Radiation Oncology, Maryland Regional Cancer Center, Silver Spring, MD; ¶¶Department of Surgery, Rush University Medical Center, Chicago, IL; ∥∥Department of Clinical Affairs, Xoft, Inc, Sunnyvale, CA; and ***Office of Advanced Technology and Science, Xoft, Inc, Sunnyvale, CA.
Supported by Xoft, Inc.
K. Dowlatshahi has received speaker honorarium from Xoft, Inc. A. Dickler is a member of the Xoft, Inc. Clinical Advisory Board. V. Mehta consults on training and has received speaker honorarium from Xoft, Inc. K. Haile and D. Wazer have received speaker honorarium from Xoft, Inc. S. Kurtzman is a prior medical advisor for Xoft, Inc. and owns stock. K. W. Elliott and T. W. Rusch are employees in clinical research at Xoft, Inc.
Reprints: Vivek K. Mehta, MD, Department of Radiation Oncology, Swedish Cancer Institute, 1221 Madison Street, Seattle, WA 98104. E-mail: firstname.lastname@example.org.